A generalization of the octonion Fourier transform to 3-D octonion-valued signals: properties and possible applications to 3-D LTI partial differential systems

Multidimensional Systems and Signal Processing - The paper is devoted to the development of the octonion Fourier transform (OFT) theory initiated in 2011 in articles by Hahn and Snopek. It is also...     

On the effectiveness of early life cycle defect prediction with Bayesian Nets

Standard practice in building models in software engineering normally involves three steps: collecting domain knowledge (previous results, expert knowledge); building a skeleton of the model based on step 1 including as yet unknown parameters; estimating the model parameters using historical data. Our experience shows that it is extremely difficult to obtain reliable data of the required granularity, or of the required volume with which we could later generalize our conclusions. Therefore, in searching for a method for building a model we cannot consider methods requiring large volumes of data. This paper discusses an experiment to develop a causal model (Bayesian net) for predicting the number of residual defects that are likely to be found during independent testing or operational usage. The approach supports (1) and (2), does not require (3), yet still makes accurate defect predictions (an R ² of 0.93 between predicted and actual defects). Since our method does not require detailed domain knowledge it can be applied very early in the process life cycle. The model incorporates a set of quantitative and qualitative factors describing a project and its development process, which are inputs to the model. The model variables, as well as the relationships between them, were identified as part of a major collaborative project. A dataset, elicited from 31 completed software projects in the consumer electronics industry, was gathered using a questionnaire distributed to managers of recent projects. We used this dataset to validate the model by analyzing several popular evaluation measures (R ², measures based on the relative error and Pred). The validation results also confirm the need for using the qualitative factors in the model. The dataset may be of interest to other researchers evaluating models with similar aims. Based on some typical scenarios we demonstrate how the model can be used for better decision support in operational environments. We also performed sensitivity analysis in which we identified the most influential variables on the number of residual defects. This showed that the project size, scale of distributed communication and the project complexity cause the most of variation in number of defects in our model. We make both the dataset and causal model available for research use.     

Reactive path integral quantum simulations of molecules solvated in superfluid helium

A hybrid ab initio   path integral molecular dynamics/bosonic path integral Monte Carlo simulation method has been developed, implemented and tested, which allows for the reactive simulations of molecules, clusters or complexes solvated by superfluid ⁴${}^4$He. The simulation takes into account “on-the-fly” the electronic structure and thus the chemical reactivity of the solutes, in conjunction with the Bose–Einstein statistics, and thus the superfluid character of this peculiar solvent. This enables investigations into cryochemical reactions taking place in helium nanodroplets, such as those used in helium nanodroplet isolation (HENDI) spectroscopy.     

Applying the boundary element method to electrochemical calculations of primary current distribution

The computation of primary current distribution using the boundary element method has been analysed. A numerical example has been included. Values obtained numerically have been compared with those obtained experimentally. A fairly good accuracy has been observed. Some computational problems occurring when using the boundary element method for electrochemical problems have been discussed.     

Cost-Benefit Analysis of Dam Projects: The Perspectives of Resettled and Non-resettled Communities

The research focuses on the perception of the Mucharz reservoir in relation to costs and benefits for two types of communities. The primary aim of the paper is to compare the social impact of dam projects among both resettled and non-resettled local communities. The secondary aim of the paper is to test multivariate analysis of variance (MANOVA) as a tool to examine the social impact assessment (SIA) of dam projects. The studied dam is located on the Skawa River within the Polish Carpathians. We used in-depth interviews with a non-resettled (N?=?96) and resettled (N?=?57) local population. To analyse the collected data, we performed multivariate analysis of variance. The main results indicate that the social assessment of dam projects differs significantly depending on whether one belongs to the group of resettled or non-resettled population. MANOVA is an effective tool for the analysis of the social impact assessment (SIA) of dam projects.

     

Central limit theorem for reducible and irreducible open quantum walks

In this work we aim at proving central limit theorems for open quantum walks on \({\mathbb {Z}}^d\). We study the case when there are various classes of vertices in the network. In particular, we investigate two ways of distributing the vertex classes in the network. First, we assign the classes in a regular pattern. Secondly, we assign each vertex a random class with a transition invariant distribution. For each way of distributing vertex classes, we obtain an appropriate central limit theorem, illustrated by numerical examples. These theorems may have application in the study of complex systems in quantum biology and dissipative quantum computation.     

Structural damage identification by adding virtual masses

This paper presents a method for damage identification by adding virtual masses to the structure in order to increase its sensitivity to local damages. The main concept is based on the Virtual Distortion Method (VDM), which is a fast structural reanalysis method that employs virtual distortions or pseudo loads to simulate structural modifications. In this paper, the structure with an added virtual mass is called the virtual structure. First, the acceleration frequency response of the virtual structure is constructed numerically by the VDM using local dynamic data measured only by a single excitation sensor and a single acceleration sensor. Second, the value of the additional mass is determined via sensitivity analysis of the constructed frequency responses of the virtual structure with respect to damage parameters; only the natural frequencies with high sensitivity are selected. This process is repeated for all the considered placements of the virtual mass. At last, the selected natural frequencies of all the virtual structures are used together for damage identification of the real structure. A finite element (FE) model of a plane frame is used to introduce and verify the proposed method. The damage can be identified precisely and effectively even under simulated 5 % Gaussian noise pollution.     

Non-local line method for notched elements with use of effective length calculated in an elasto-plastic condition

The paper presents a non-local line method used to the fatigue life calculation of notched elements. The presented method is based on the concept of an effective length which determines the size of the equivalent fatigue zone. Effective values of normal stress calculated in the critical plane with a weight function were applied when determining the equivalent fatigue zone. Simulation studies were performed for two types of steel and two types of loading. Five different series of tests and simulations were used. Experimental studies were carried out for 40 HM-T and EA4T steels. These materials are used in railway industry, including the manufacturing of coupling bars. The notched test specimens contained notches with a tip radius of 0.2, 0.5, 0.8 and 1 mm. Stress calculations were performed using the finite element method by adopting cyclic material properties described by the model of a multi-linear hardening. Non-local calculations were performed in a defined critical plane for normal stress distribution and a weight function. As a result, the function of variation of the effective length depending on the loading level and geometry of the notch has been determined.