Matjaž Depolli

Jožef Stefan Institute | IJS · Department of Communication Systems

In this paper, we present a reconstruction of climate conditions during the Last Glacial Maximum on a karst plateau Snežnik, which lies in Dinaric Mountains (southern Slovenia) and bears evidence of glaciation. The reconstruction merges geomorphological ice limits, classified as either clear or unclear, and a computer modelling approach based on th...

In this paper we present a reconstruction of climate conditions during the Last Glacial Maximum on a karst plateau in Dinaric Mountains (southern Slovenia) that bares evidence of glaciation. The reconstruction merges geomorphological ice limits, classified as either clear or unclear, and computer modelling approach based on Parallel Ice Sheet Model...

This study addresses the critical challenges of time synchronization in wearable sensor networks, focusing on electrocardiogram (ECG) and inertial measurement unit (IMU) monitoring applications. In the era of continuous physiological and biomechanical monitoring, accurate time synchronization of sensor data is critical. Our research investigates th...

Transmission system operators (TSOs) in recent years have faced challenges in order to ensure maximum transmission capacity of the system to satisfy market needs, while maintaining operational safety and permissible impact on the environment. A great help in the decision-making process was introduced with the Dynamic Thermal Rating (DTR) - an instr...

The paper analyses the autonomy of a wireless body sensor that continuously measures the potential difference between two proximal electrodes on the skin, primarily used for measuring an electrocardiogram (ECG) when worn on the torso. The sensor is powered by a small rechargeable battery and is designed for extremely low power use. However, the aut...

In this paper, we present a novel parallel dimension-independent node positioning algorithm that is capable of generating nodes with variable density, suitable for mesh-less numerical analysis. A very efficient sequential algorithm based on Poisson disc sampling is parallelized for use on shared-memory computers, such as the modern workstations wit...

In this paper, we present a novel parallel dimension-independent node positioning algorithm that is capable of generating nodes with variable density, suitable for meshless numerical analysis. A very efficient sequential algorithm based on Poisson disc sampling is parallelized for use on shared-memory computers, such as modern workstations with mul...

Transmission system operators (TSOs) in recent years have faced challenges in order to ensure maximum transmission capacity of the system to satisfy market needs, while maintaining operational safety and permissible impact on the environment. A great help in the decision-making process was introduced with the Dynamic Thermal Rating (DTR) - an instr...

Point sampling in interiors and on surfaces of 3D bodies has important applications in computer graphics, visualization and physical simulations. Some of those application require certain statistical properties of the generated sample, but many don't and it is often only desired that the final points are distributed quasi regularly, with approximat...

One of the traditional ways of solving the maximum common induced subgraph problem is by reduction to a maximum clique problem. The two input graphs, in which the maximum common subgraph is to be found, are multiplied to form a product graph, which is then input to the maximum clique algorithm. The result of the latter are used to identify the node...

The recent trend in electrocardiogram (ECG) device development is towards wireless body sensors applied for patient monitoring. The ultimate goal is to develop a multi-functional body sensor that will provide synchronized vital bio-signs of the monitored user. In this paper, we present an ECG sensor for long-term monitoring, which measures the surf...

A contact problem is simulated in a setting of fretting fatigue applications. Surface stresses are analysed in order to determine the conditions for crack initiation. The solution approach is based on a weak formulated MLPG meshless method. Surface boundary tractions are obtained from analytical solution of Hertzian model. To manage the computation...

We present numerical computation of stresses under fretting fatigue conditions derived from closed form expressions. The Navier-Cauchy equations, that govern the problem, are solved with strong and weak form meshless numerical methods. The results are compared to the solution obtained from well-established commercial package ABAQUS, which is based...

The content of our book, devoted to body sensors and their implications to electrocardiography, is recapitulated with this chapter. The identified challenges in long-term ECG data analytics are discussed. Based on the presented material, the near future of mHealth perspectives is foreseen regarding the technology, the usability, and the potential o...

Besides the standard 12-lead ECG and the Holter monitor, today the market offers a wide range of modern ECG devices and services supported by the latest developments in ICT. This chapter is devoted to the current state-of-the-art from the area of ECG with a reduced number of leads. We focus on ECG wireless body sensors, differentiating between thos...

A description of software requirements for an mHealth system is provided. Several layers of software are required for proper system functioning: ECG body sensor firmware, applications on smartphones, Cloud applications, and stand-alone applications for personal computers. The main functionality requirements of the mHealth software are described. Ad...

The use of wireless ECG body sensors in two pilot studies is presented. The first study, running at the Department of Cardiovascular Surgery of the University Medical Centre Ljubljana, is focused on the investigation of postoperative atrial fibrillation. The patients are monitored with wireless ECG body sensors one day before and five days after th...

A more detailed description of multichannel electrocardiography and the differential lead aims to clarify why the multichannel ECG opens a path towards implementation of wireless wearable sensors. Several ways of how the differential lead could be used for heart rhythm monitoring are shown with options for analysis and interpretation of sensor ECG...

This monograph presents a comprehensive overview of the electrocardiography from the aspect of wireless and mobile monitoring and its potential for personalized health management. The topical focus is on the implementation and efficient application of user friendly m-Health systems. The target audience comprises biomedical engineers, medical doctor...

The use of ICT in the health care system is aimed to increase efficacy and decrease costs. We have designed a system and services for mobile monitoring of vital physiological parameters and environmental context. The system is based on a small multi-functional wireless body sensor for simultaneous measurement of ECG, temperature, heart rate, respir...

Computer simulations of complex natural phenomena become an approach of choice if experimental work is impractical or dangerous. Often, optimization approaches are used in a closed cycle with the simulation to obtain the desired performances. To test and validate such cases an optimization of a coupled thermo-fluid transport in a two dimensional ca...

There are computationally demanding problems that can be solved by k-clique search algorithms in auxiliary product graphs. The best clique search programs heavily rely upon good colorings. But obtaining a good coloring is a demanding task itself. We present some coloring schemes that exploit the property of the product graph itself and can be const...

Fretting is a phenomenon that occurs at the contacts of surfaces that are subjected to oscillatory relative movement of small amplitudes. Depending on service conditions, fretting may significantly reduce the service life of a component due to fretting fatigue. In this regard, the analysis of stresses at contact is of great importance for predictin...

The performance of a Differential Evolution for Multi-objective Optimization (DEMO) in a non-linear coupled transport problem, solved by a Meshless Local Strong Form Method (MLSM), is assessed from different points of view. First, the behaviour of the optimization algorithm is tested for different scenarios, ranging from optimization of trivial dif...

The increasing energy consumption of large-scale high performance resources raises technical and economical concerns. A reduction of consumed energy in multicore systems is possible to some extent with an optimized usage of computing and memory resources that is tailored to specific HPC applications. The essential step towards more sustainable cons...

The introduction of information and communication technologies (ICT) into the integrated healthcare system could increase the self-management of health and therefore increase the efficacy and decrease the costs of overall health management. A personal mobile health monitoring system (PCARD) has been developed, which uses moderately-priced and user-...

Extreme Data is an incarnation of Big Data concept distinguished by the massive amounts of data that must be queried, communicated and analyzed in near real-time by using a very large number of memory or storage elements and exascale computing systems. Immediate examples are the scientific data produced at a rate of hundreds of gigabits-per-second...

In emergency situations, such as extensive natural disasters, a rapid and effective establishment of a temporary wireless mobile network for emergency communications and transmission of information is essential. The architecture of a temporary mobile network for communications in emergency situations proposed by the European project ABSOLUTE consis...

This chapter focuses the point interpolation called local radial basis function collocation method (LRBFCM). The main advantage of local numerical methods is that their system matrix is sparse or banded, which simplifies the solution procedure. Then it explores how the complex memory hierarchy, in particular the L3 cache, affects a parallel program...

This article deals with the minimization of the energy transport through the isolated enclosure by means of obstructing the fluid flow. The differentially heated cavity is partially covered with non-permeable obstacles that affect the natural convection flow. We seek the optimal position and shape of the obstacles to minimize the heat flux through...

a b s t r a c t The performance of the parallel implementation of the local meshless numerical method in solving sys-tem of coupled partial differential equations is explored. Presented numerical approach makes the com-putation convenient for parallel implementation using OpenMP based parallelisation. The numerical experiments are performed on the...

The performance of the parallel implementation of the local meshless numerical method in solving sys-tem of coupled partial differential equations is explored. Presented numerical approach makes the com-putation convenient for parallel implementation using OpenMP based parallelisation. The numerical experiments are performed on the de Vahl Davis na...

Biologists have been investigating plant defence response to virus infections; however, a comprehensive mathematical model of this complex process has not been developed. One obstacle in developing a dynamic model, useful for simulation, is the lack of kinetic data from which the model parameters could be determined. We address this problem by prop...

A new exact parallel maximum clique algorithm MaxCliquePara, which finds the maximum clique (the fully connected subgraph) in undirected general and protein graphs, is presented. First, a new branch and bound algorithm for finding a maximum clique on a single computer core, which builds on ideas presented in two published state of the art sequentia...

Hadoop MapReduce has become one of the most popular tools for data processing. Hadoop is normally installed on a cluster of computers. When the cluster becomes undersized, it can be scaled by adding new computers and storage devices, but it can also be extended by real or virtual resources from another computer cluster. We present a utilization of...

The paper describes the application of Hadoop modules: MapReduce, Pig and Hive, for processing and analyzing large amounts of tabular data acquired from a computer simulation of heat transfer in bio tissues. The Apache Hadoop is an open source environment for storing and analyzing BigData. It was installed on a cluster of six computing nodes, each...

In this paper, the code for the North Atlantic Princeton Ocean Model (NAPOM) used by the Marine Biology Station (MBS) is parallelized and optimized. The FORTRAN source code and the hardware architecture of MBS cluster are examined and analyzed to determine the behavior of the NAPOM execution with bottlenecks identified on both ends. Based on the an...

The ever-increasing energy consumption in large-scale distributed computing systems such as clusters, grids and clouds raises social, technical, economical, and environmental concerns. Therefore, designing novel energy-efficient approaches, to reduce energy consumption, at all levels of distributed system architecture is of great importance for the...

The ProBiS algorithm performs a local structural comparison of the query protein surface against the nonredundant database of protein structures. It finds proteins that have binding sites in common with the query protein. Here, we present a new parallelized algorithm, Parallel-ProBiS, for detecting similar binding sites on clusters of computers. Th...

Biologists have been investigating the plant defense response to virus infections for a long time. Nevertheless, its model has still not been developed. One of the reasons is the deficiency in numerical kinetic data that brings up the importance of the expert knowledge. Therefore, we based our work on acquiring domain knowledge of biological pathwa...

Abstract In this paper, we present AMS-DEMO, an asynchronous master-slave implementation of DEMO, an evolutionary algorithm for multi-objective optimization. AMS-DEMO was designed for solving time-intensive problems efficiently on both homogeneous and heterogeneous parallel computer architectures. The algorithm is used as a test case for the asynch...

This paper analyses the application of OpenMP parallelization on shared-memory systems, such as the increasingly available multicore systems. The parallelization of the local meshless numerical method is considered. The presented solution procedure is suitable for solving systems of coupled partial differential equations. The superlinear speedup is...

Temperature changes in the resting proximal human forearm have been studied non-invasively, using computer simulation. A procedure for spatial model generation, based on digitized slice data, has been applied. A mathematical model and a 3-D computer simulation program have been implemented. Heat transfer in the non-homogenous tissue was modeled wit...

The spectrum of non-uniformly sampled signals is often needed for analysis of signals obtained from network of distributed sensors. In this paper, we analyze a method to retrieve the spectrum of this type of signals through interpolation, then re-sampling with uniform rate and performing Fourier transform at the end. We discuss this method based on...

A wireless bipolar body electrode has been developed, taking into account the limitations posed by signal-to-noise ratio, dimensions, wireless technology, limited power consumption and requirements for post-processing. A small set of wireless bipolar electrodes, placed at optimal locations on the body surface, are connected into a network that is a...

An improved model of action potentials (AP) is proposed to increase the accuracy of simulated electrocardiograms (ECGs). ECG simulator is based on a spatial model of a left ventricle, composed of cubic cells. Three distinct APs, modeled with functions proposed by Wohlfard, have been assigned to the cells, forming epicardial, mid, and endocardial la...

Evolutionary computation is an area of computer science utilizing the mechanisms of biological evolution in computer problem solving. It is concerned with theoretical studies, design and application of stochastic optimization procedures, known as Evolutionary Algorithms (EAs). EAs have proven effective and robust in solving demanding optimization p...

An improved model of action potentials (AP) is proposed to increase the accuracy of simulated electrocar-diograms (ECGs). ECG simulator is based on a spatial model of a left ventricle, composed of cubic cells. Three distinct APs, modeled with functions proposed by Wohlfard, have been assigned to the cells, forming epicardial, mid, and endocardial l...

Several hypotheses for the origin of the U wave in electrocardiograms have been proposed. We have set out to explore and test alternative modes for U-wave genesis via computer simulations. A spatial model of a left ventricle has been constructed from 12 layers composed of cubic cells. Each cell is assigned its own time-dependent action potential wi...

Solving real-life optimization problems numerically is often very time demanding, because of high complexity of the simulations that are usually involved in evaluation of solutions. Solving such problems thus becomes highly impractical. Fortunately, evolutionary algo-rithms, often used in numerical optimization, can be parallelized with relative ea...