Extraction of chemical information of suspensions using radiative transfer theory to remove multiple scattering effects: application to a model multicomponent system

The effectiveness of a scatter correction approach based on decoupling absorption and scattering effects through the use of the radiative transfer theory to invert a suitable set of measurements is studied by considering a model multicomponent suspension. The method was used in conjunction with partial least-squares regression to build calibration models for estimating the concentration of two types of analytes: an absorbing (nonscattering) species and a particulate (absorbing and scattering) species. The performances of the models built by this approach were compared with those obtained by applying empirical scatter correction approaches to diffuse reflectance, diffuse transmittance, and collimated transmittance measurements. It was found that the method provided appreciable improvement in model performance for the prediction of both types of analytes. The study indicates that, as long as the bulk absorption spectra are accurately extracted, no further empirical preprocessing to remove light scattering effects is required.     

Visual syntax does matter: improving the cognitive effectiveness of the i* visual notation

Goal-oriented modelling is one of the most important research developments in the requirements engineering (RE) field. This paper conducts a systematic analysis of the visual syntax of i*, one of the leading goal-oriented languages. Like most RE notations, i* is highly visual. Yet surprisingly, there has been little debate about or modification to its graphical conventions since it was proposed more than a decade ago. We evaluate the i* visual notation using a set of principles for designing cognitively effective visual notations (the Physics of Notations). The analysis reveals some serious flaws in the notation together with some practical recommendations for improvement. The results can be used to improve its effectiveness in practice, particularly for communicating with end users. A broader goal of the paper is to raise awareness about the importance of visual representation in RE research, which has historically received little attention.     

Multi-level privacy analysis of business processes: the Pleak toolset

International Journal on Software Tools for Technology Transfer - Privacy regulations, such as GDPR, impose strict requirements to organizations that store and process private data....     

Quantitative spectroscopic analysis of heterogeneous mixtures: the correction of multiplicative effects caused by variations in physical properties of samples

Spectral measurements of complex heterogeneous types of mixture samples are often affected by significant multiplicative effects resulting from light scattering, due to physical variations (e.g., particle size and shape, sample packing, and sample surface, etc.) inherent within the individual samples. Therefore, the separation of the spectral contributions due to variations in chemical compositions from those caused by physical variations is crucial to accurate quantitative spectroscopic analysis of heterogeneous samples. In this work, an improved strategy has been proposed to estimate the multiplicative parameters accounting for multiplicative effects in each measured spectrum and, hence, mitigate the detrimental influence of multiplicative effects on the quantitative spectroscopic analysis of heterogeneous samples. The basic assumption of the proposed method is that light scattering due to physical variations has the same effects on the spectral contributions of each of the spectroscopically active chemical components in the same sample mixture. On the basis of this underlying assumption, the proposed method realizes the efficient estimation of the multiplicative parameters by solving a simple quadratic programming problem. The performance of the proposed method has been tested on two publicly available benchmark data sets (i.e., near-infrared total diffuse transmittance spectra of four-component suspension samples and near-infrared spectral data of meat samples) and compared with some empirical approaches designed for the same purpose. It was found that the proposed method provided appreciable improvement in quantitative spectroscopic analysis of heterogeneous mixture samples. The study indicates that accurate quantitative spectroscopic analysis of heterogeneous mixture samples can be achieved through the combination of spectroscopic techniques with smart modeling methodology.     

The impact of Na2O on the synthesis of α-C2SH with different mineral composition and the stability of intermediate and final products

In this work the effect of Na₂O on the synthesis of α-C₂S hydrate (2CaO·SiO₂·H₂O), named as α-C₂SH, with different mineral composition and the stability of intermediate and final products were investigated. It is worth noting that new results was discovered by evaluating the mineral composition of hydrothermally synthesized α-C₂SH samples (200?°C; 2–72?h). It was found that Na₂O additive significantly influenced the formation and stability of intermediate and final products: within 12?h of hydrothermal treatment together with α-C₂SH a new calcium silicate hydrate phase, killalaite, was obtained in the products. Besides, the mineral composition of formed compounds slightly varied by prolonging the duration of synthesis to 24?h. For the first time it was proved that Na⁺ ions are not incorporated into the crystal structure of the main synthesis product, α-C₂SH. On the contrary, the mentioned ions are intercalated into the crystal structure of other calcium silicate hydrates. Moreover, the investigated alkaline additive reduced the recrystallization temperature of the synthesis products to wollastonite by 50?°C and significantly decreased the values of both specific area and total pore volume of α-C₂SH till 8.496?m²/g and 0.05084?cm³/g, respectively. The synthetic products were characterized by XRD, DSC, SEM/EDX and N₂ adsorption analysis.     

Evaluation of ischemic injury of the cardiac tissue by using the principal component analysis of an epicardial electrogram

Monitoring and control of the heart tissue viability is of crucial importance during heart surgery operations. In most cases the heart tissue suffers from an ischemic injury that causes a decrease in the velocity of electrical excitation propagation in it and influences the shape of the excitation wave front that spreads over the injured area. It is reflected in a more complex shape of the registered epicardial electrogram as compared to normal. A method for quantitative evaluation of the complexity of the shape of the epicardial electrogram based on the principal component analysis is here proposed for evaluation of the ischemic injury of the cardiac tissue. A minimal, yet sufficient, number of the principal components (the optimal basis functions) for truncated expansion of the epicardial electrogram signals could be used as an estimate of signal complexity. The method for determination of such a minimal, yet sufficient, number of principal components were developed by using epicardial electrograms registered during in situ experiments on dogs in which local ischemia was evoked by ligation of a coronary vessel.     

Scientific publications released in the Baltic States

The article focuses on evolution of scientific publications released in the Baltic States (Lithuania, Latvia and Estonia) and refers to international databases that contain scientific papers produced over the last 20 years of independence. The countries share the same history of restoration of independence after 40 years of occupation. The article shall specifically focus on the period of post EU accession in 2004. It will discuss the contribution of Kaunas University of Technology, Vilnius Gediminas Technical University, Riga Technical University and Tallinn University of Technology to the total number of publications in these countries. The investigation was based on databases of Thomson Reuters Web of Science, Essential Science Indicators and Journal Citation Report. Additionally, it employed the Scimago ranking system based on Scopus database. Data analysis also involved similar indices that provide the number of papers and their citation results as well as the average number of citations per paper.