Maritime surveillance: Tracking ships inside a dynamic background using a fast level-set

Surveillance in a maritime environment is indispensable in the fight against a wide range of criminal activities, including pirate attacks, unlicensed fishing trailers and human trafficking. Computer vision systems can be a useful aid in the law enforcement process, by for example tracking and identifying moving vessels on the ocean. However, the maritime domain poses many challenges for the design of an effective maritime surveillance system. One such challenge is the tracking of moving vessels in the presence of a moving dynamic background (the ocean). We present techniques that address this particular problem. We use a background subtraction method and employ a real-time approximation of level-set-based curve evolution to demarcate the outline of moving vessels in the ocean. We report promising results on both small and large vessels, based on two field trials.     

The Use of Context-Free Probabilistic Grammar to Anonymise Statistical Data

Abstract

In the following article, a proprietary method of anonymisation of identifiable statistical data using context-free probabilistic grammar is proposed. The advantage of this method is that it is simple and thanks to this, the identifier is easy to retrieve after masking the identifiable data, e.g. when it is necessary to modify or update the micro-data. This can be done using public-key cryptography, i.e. encrypting some probabilistic context-free grammar with this method. In the case of public statistics, there is often a need to use an anonymised source value, for example when economic operators’ reports are verified by statistical officers. With appropriate information generated by context-free grammar, the verifier can easily identify an economic operator or a natural person. The idea of the anonymising algorithm used in the proposed method is presented by means of an example. According to the authors, the combination of the proposed method with asymmetric encryption of the definition of context-free grammar using public key infrastructure, makes it probable that its resistance to attacks will be quite high. This is because statistical methods that are used in the analysis of natural languages are not susceptible to attacks.     

A new approach towards controlled synthesis of multifunctional core-shell nano-architectures: luminescent and superparamagnetic

We have developed a two-step method for synthesis of multifunctional core-shell nanoparticles with an improved structure as compared with those prepared by traditional methods used independently. The nanoparticles comprise a superparamagnetic core, an inner insulating dye-free silica shell, an outer luminescent silica shell encapsulating thousands of dye molecules and a functionalizeable surface. The innovative insertion of the isolating silica shell benefits the nanoparticles' architecture in two ways. Firstly, by keeping the dye molecules away from the magnetic core, the silica shell prevents dye luminescence quenching. Secondly, the non-magnetic shell decreases magnetic interparticle coupling, which, by reducing aggregation and preventing agglomeration, facilitates the formation of the high-quality luminescent shell in the second step of the process. The final nanoparticles being both superparamagnetic and luminescent have a great potential for theranostic applications such as ultra-sensitive detection, and in-vitro and in-vivo imaging.     

Physicochemical and sensory properties of goat cheeses and their fatty acid profile in relation to the geographic region of production

The aim of the study was to evaluate the chemical composition, colour and sensory profile of rennet goat cheeses, taking into account their geographic region of production. The relationships between the botanical composition of the goats’ pasture to the fatty acid (FA) profiles and health indicators of the fat of cheese produced from their milk in artisanal conditions were also determined. Grazing of goats on natural pastures with greater floristic richness and, above all, the presence of more meadow species and herbs, not only increased the proportions of beneficial FAs in the cheese but also improved sensory characteristics valued by consumers.     

Structural analysis of tars from fluidized-bed pyrolysis of coal. 1. Gas-liquid chromatography of aliphatic and aromatic subfractions

The effect of pyrolysing gas composition on the low-molecular-weight aliphatic and aromatic components of fluidized-bed tars has been investigated. Two tars from the rapid pyrolysis of coal in a fluidized-bed were solvent-fractionated into oils, asphaltenes and benzene-insoluble materials. The aliphatic and low-molecular-weight aromatic subfractions of the oils were then analysed by glass-capillary column gas-liquid chromatography. The results show that pyrolysis in a more active atmosphere of char gasification gases is ‘deeper’, and, to some extent, similar to hydrogen-assisted pyrolysis; the yield of tar is higher, and the product has higher aromaticity and average molecular weight compared with pyrolysis in nitrogen-rich flue gases.     

Influence of synthesis method on the properties of mixed Aurivillius phase Bi5TiNbWO15

The ceramic material Bi₅TiNbWO₁₅ (BTNW) was obtained and is characterized by a layered, Aurivillus type structure (MBLPO—mixed bismuth oxide layered perovskites) with m = 1.5. In order to optimize the production, BTNW was synthesized by two methods: synthesis of a mixture of simple oxides Bi₂O₃, Nb₂O₅, WO₃, TiO₂ and synthesis of a mixture of appropriate, layered Aurivillus type structures Bi₂WO₆ (m = 1) and Bi₃TiNbO₉ (m = 2). Synthesized solid solutions were consolidated with a conventional method. The crystal structure of Bi₂WO₆ and Bi₃TiNbO₉ Bi₅TiNbWO₁₅ was examined at room temperature with an X-ray diffraction method. Microstructure and chemical composition were analyzed. The authors analyzed the temperature—permittivity ɛ relationship for the ceramic with m = 1,5, which was obtained with two methods, as well as for m = 1 and m = 2.     

Myoglobin immunoassay utilizing directional surface plasmon-coupled emission

We described an immunoassay for the cardiac marker myoglobin on a thin silver mirror surface using surface plasmon-coupled emission (SPCE). SPCE occurs for fluorophores in proximity (within approximately 200 nm) of a thin metal film (in our case, silver) and results in a highly directional radiation through a glass substrate at a well-defined angle from the normal axis. We used the effect of SPCE to develop a myoglobin immunoassay on the silver mirror surface deposited on a glass substrate. Binding of the labeled anti-myoglobin antibodies led to the enhanced fluorescence emission at a specific angle of 72 degrees . The directional and enhanced directional fluorescence emission enables detection of myoglobin over a wide range of concentrations from subnormal to the elevated level of this cardiac marker. Utilizing SPCE allowed us also to demonstrate significant background suppression (from serum or whole blood) in the myoglobin immunoassay. We expect SPCE to become a powerful technique for performing immunoassays for many biomarkers in surface-bound assays.     

Hammerstein system identification by the Haar multiresolution approximation

The paper deals with recovering non‐linearities in the Hammerstein systems using the multiresolution approximation—a basic concept of wavelet theory. The systems are driven by random signals and are disturbed by additive, white or coloured, random noise. The a priori information about system components is non‐parametric and a delay in the dynamical part of systems is admitted. A non‐parametric identification algorithm for estimating non‐linear characteristics of static parts is proposed and investigated. The algorithm is based on the Haar multiresolution approximation. The pointwise convergence and the pointwise asymptotic rate of convergence of the algorithm are established. It is shown that neither the form nor the convergence conditions of the algorithm need any modification if the noise is not white but correlated. Also the asymptotic rate of convergence is the same for white and coloured noise. The theoretical results are confirmed by computer simulations. Copyright © 1999 John Wiley & Sons, Ltd.     

The dynamic stability of a crane standing on soil during the rotation of the boom

In this work the influence of flexible soil foundation on the dynamic stability of the boom crane is presented. This analysis was made during the rotation of the boom, such that variable pressure on the soil and other deformations could be taken into account. The rheological deformation of the soil as a function of the changing strain in time has been described by an equation, which is the Duhamel integral. After accepting the discrete model of the considered system dynamic equations of motion were elaborated, which because of their nonlinearity and complexity were solved numerically. Appointed were the dynamic displacements of each of the supports for different rotational speeds of the boom, showing the influence of the rheological deformation of the soil on the behaviour of the whole crane. As well the trajectories of the motion of the weight hoisted were presented for different rotational speeds of the boom, which enabled the analysis of the precision of the positioning of the weight being hoisted (minimization of oscillation).