Valuations for spike train prediction

The ultimate product of an electrophysiology experiment is often a decision on which biological hypothesis or model best explains the observed data. We outline a paradigm designed for comparison of different models, which we refer to as spike train prediction. A key ingredient of this paradigm is a prediction quality valuation that estimates how close a predicted conditional intensity function is to an actual observed spike train. Although a valuation based on log likelihood (L) is most natural, it has various complications in this context. We propose that a quadratic valuation (Q) can be used as an alternative to L. Q shares some important theoretical properties with L, including consistency, and the two valuations perform similarly on simulated and experimental data. Moreover, Q is more robust than L, and optimization with Q can dramatically improve computational efficiency. We illustrate the utility of Q for comparing models of peer prediction, where it can be computed directly from cross-correlograms. Although Q does not have a straightforward probabilistic interpretation, Q is essentially given by Euclidean distance.     

The determination of dust cloud altitudes from a satellite using hyperspectral measurements in the gaseous absorption band

An approach to derive dust layer optical thickness and top height using top-of-atmosphere (TOA) reflectance in the oxygen A-band is introduced. The algorithm is similar to that developed by the authors for the case of water clouds. It is based on the fitting of spectral TOA reflectance measurements in the narrow band around 760 nm using results of the exact radiative transfer calculations for a given dust layer model. The accuracy of the technique with respect to the uncertainty in a priori assumption of the dust single-scattering albedo is discussed. The algorithm is applied to satellite hyperspectral measurements over the Atlantic Ocean.     

Russian scatterometer: discussion of the concept and the numerical simulation of wind field retrieval

Orbital scatterometry is briefly overviewed and its trends are indicated. Two scatterometer concepts are currently considered for trade-offs: with fixed and rotating antenna systems. The concept with a rotating antenna system was selected and SeaWinds was chosen as the prototype for the first Russian scatterometer. The scatterometer concept was then further developed and instead of two pencil beams, a fan-beam antenna was proposed (about 1° × 6°). The fan-beam antenna allows successive measurements for horizontal and vertical polarization in each wind vector cell (WVC). This increases the number of observations of the WVC at different incidence and azimuth angles during flight. The scatterometer parameters required to implement the proposed measurement geometry for an orbit altitude of 650 km and a swath width of 1525 km are discussed. A numerical scatterometer model that accounts for both the specifications and the observation geometry is developed. The scatterometer performance, with subsequent formation of a swath and splitting into WVCs, is simulated. The procedure of wind vector retrieval includes two stages: 1) determining wind speed and wind direction in a single WVC; and 2) using the information from adjacent WVCs to correct wind direction. It is shown that the accuracy of wind direction retrieval by a WVC can be increased by simultaneous radar cross-section (RCS) measurements at vertical and horizontal polarization. The basic error in determining wind direction is due to a 180° wind direction ambiguity caused by the form of RCS azimuth dependence. Two-dimensional median filtering is commonly employed in scatterometry to increase the accuracy of wind direction retrieval. In this study, two-dimensional angular median filtering was employed and it is shown that the error in wind direction retrieval significantly decreased. The results of the research indicate that wind field can be retrieved by the new scatterometer with the level of precision required.     

A survey on peer-to-peer SIP based communication systems

Recently, both academia and industry have initiated research projects directed on integration of P2PSIP paradigm into communication systems. In this paradigm, P2P network stores most of the network information on each participating peer without help of the central servers. The concept of self-configuration, self-establishment greatly improves the robustness of the network system compared with the traditional Client/Server based systems. In this paper, we survey P2PSIP solutions proposed recently both in the academic and industrial research. We consider technical issues that include Chord overlay topology, P2PSIP session initiation (including enrollment and bootstrap, NAT traversal, message routing, P2PSIP interworking, P2PSIP Client, etc), and security issues. Our survey is based on recent research publications.     

Theory of optimal residual stresses and defects distribution

Residual stress plays an important role with respect to the operating performance of mechanical parts. Its effect on the different properties of a material (fatigue, fracture, corrosion, friction, wear, etc.) can be considerable. In the modern design of mechanical components, residual stress has therefore to be taken into account. In the present article, the mathematical theory of optimal residual stresses and strains is introduced.     

Graph-based technique for survivability assessment and optimization of IoT applications

International Journal on Software Tools for Technology Transfer - The Internet of Things (IoT) has evolved from theoretical research to market deployment. The IoT will enable a plethora of new...     

Decision-cache based XACML authorisation and anonymisation for XML documents

This paper describes a decision cache for the eXtensible Access Control Markup Language (XACML) that supports fine-grained authorisation and anonymisation of XML based messages and documents down to XML attribute and element level. The decision cache is implemented as an XACML obligation service, where a specification of the XML elements to be authorised and anonymised is sent to the Policy Enforcement Point (PEP) during initial authorisation. Further authorisation of individual XML elements according to the authorisation specification is then performed on all matching XML resources, and decisions are stored in the decision cache. This makes it possible to cache fine-grained XACML authorisation and anonymisation decisions, which reduces the authorisation load on the Policy Decision Point (PDP). The theoretical solution is related to a practical case study consisting of a privacy-enhanced intrusion detection system that needs to perform anonymisation of Intrusion Detection Message Exchange Format (IDMEF) XML messages before they are sent to a security operations centre that operates in privacy-preserving mode. The solution increases the scalability of XACML based authorisation significantly, and may be instrumental in implementing federated authorisation and anonymisation based on XACML in several areas, including intrusion detection systems, web services, content management systems and GRID based authentication and authorisation.     

Photoactive mussels inspired polymer coatings: Preparation and antibacterial activity

In this article we report on the facile preparation of photoactive antibacterial mussel inspired polymer coatings deposited on a stainless steel (SS) substrate from water based precursors. The coating is prepared by the sequential deposition of aqueous based solutions of an anchoring layer based on bio-inspired glue, a cationic polymer bearing pendent catechols, a nanogel decorated by ortho-quinones and a photosensitizer of the aminoacridine type. This latter is grafted to the coating by reaction of its amino group with the o-quinone of the deposited nanogel. The deposition of all layers is followed in-line by Quartz crystal microbalance coupled with dissipation (QCM-D) and AFM shows that the thin polymer film repeated the roughness of the SS substrate. The prepared coatings show good mechanical properties applying nanoindentation techniques. The established antibacterial activity of the prepared photoactive polymer coatings on SS against Gram-negative E. coli strain demonstrate their potential as a power tool for medical applications.     

Tumor-Targeting Peptides Search Strategy for the Delivery of Therapeutic and Diagnostic Molecules to Tumor Cells

Background: The combination of the unique properties of cancer cells makes it possible to find specific ligands that interact directly with the tumor, and to conduct targeted tumor therapy. Phage display is one of the most common methods for searching for specific ligands. Bacteriophages display peptides, and the peptides themselves can be used as targeting molecules for the delivery of diagnostic and therapeutic agents. Phage display can be performed both in vitro and in vivo. Moreover, it is possible to carry out the phage display on cells pre-enriched for a certain tumor marker, for example, CD44 and CD133. Methods: For this work we used several methods, such as phage display, sequencing, cell sorting, immunocytochemistry, phage titration. Results: We performed phage display using different screening systems (in vitro and in vivo), different phage libraries (Ph.D-7, Ph.D-12, Ph.D-C7C) on CD44+/CD133+ and without enrichment U-87 MG cells. The binding efficiency of bacteriophages displayed tumor-targeting peptides on U-87 MG cells was compared in vitro. We also conducted a comparative analysis in vivo of the specificity of the accumulation of selected bacteriophages in the tumor and in the control organs (liver, brain, kidney and lungs). Conclusions: The screening in vivo of linear phage peptide libraries for glioblastoma was the most effective strategy for obtaining tumor-targeting peptides providing targeted delivery of diagnostic and therapeutic agents to glioblastoma.