A True Random Numbers Service and its Applications

Abstract - We shall give an overview of random number generators in scientific use today, concentrating on the ”truly random” ones. Quantum Random Bits Generator Service shall serve as an example of these, being readily available – online and free, with known qualities of served content. Sensitivity analysis of a typical stochastic scientific applications (dominantly Monte Carlo integration methods) to a choice of random numbers generator is laid out, with results showing optimal choice of

generator, concerning application-specific needs for data randomness, and speed. As a concrete real-world example of an randomnesscritical simulation, the SALUTE application is used, with results supporting the use of a truly random generators for parallel Monte Carlo simulations of physical systems.

Download link: http://www.irb.hr/hr/cir/rep/projects/cenvis/papers/A_true_random_numbers_service_and_its_application.pdf/

Fast System Matrix Generation on a GPU Cluster

Abstract - This paper presents an algorithm for Positron Emission Tomography reconstruction running on a GPU cluster. The most computation intensive part of the reconstruction process, the forward projection, is reinterpreted as a geometric problem, that can efficiently be solved by the graphics hardware. We also investigate the possibilities to further increase the speed and to sidestep the texture memory limitations by using not a single GPU, but a cluster of GPUs. To do so, the iteration scheme is modified to minimize the communication need between the GPU nodes.

Download link: http://www.irb.hr/hr/cir/rep/projects/cenvis/papers/Fast_System_Matrix_Generation_on_a_GPU_Cluster.pdf/

Intelligent algorithm for smoke extraction in autonomous forest fire detection

ABSTRACT - Forest fire, if not detected early enough, can cause great damage. In order to reduce it, it is vital to detect fire as soon as possible and act upon it. In its early stage, forest fire manifests itself primarily as smoke, as flames are too little to be seen. Therefore, to ensure forest fire detection in its earliest stages, smoke detection is utilized. Autonomous forest fire detection based on smoke detection is currently one of the greatest challenges in image processing field. The main reason for it is that there are lots of smokeresembling natural phenomena such as clouds, cloud shadows and dust. So the essence of the problem lies in separating these phenomena from real smoke. In this article we propose a smoke detection algorithm thatcombines motion detection, edge detection, spectrum analyzing and moving shape analyzing algorithms, matched together to increase detection rate and to decrease false alarm rate.

Download link: http://www.irb.hr/hr/cir/rep/projects/cenvis/papers/Intelligent_algorithm_for_smoke_extraction_in_autonomous_forest_fire_detection.pdf/

Protein Data Bank Graphics Generator

Experimental data acquired from NMR, X-ray diffraction and other experimental methods are usually stored into formatted files called PDB files that can be found at www.pdb.org.

Searching through PDB files and extracting or visually representing the results, usually requires a lot of programming or using a variety of software. To make these tasks easier we created the relational model of a database, and our web interface, which enables the user to send queries to database, retrieve the results, export them into ASCII text format or POV-Ray format and send them to a computer grid for rendering the animation.

For the needs of software development we used 143 PDB files, a PostgreSQL database, Perl scripts for importing the data from PDB files, a PHP interface with JavaScripts and a computer grid for animation rendering. The result is represented textually or in POV-Ray format with three drawing methods and five color schemes available and rendered. Application can be found at this address: http://mamlaz.irb.hr/pdb_grafika/.

Download link: http://www.irb.hr/hr/cir/rep/projects/cenvis/papers/Protein_data_bank_graphics_generator_on_grid.pdf/

Visual Analysis of Heart Reinervation after Transplantation

Abstract—During heart transplantation complete denervation of allograft occurs. Partial reinnervation may develop after one year or later. It can be detected by scintigraphy, positron emission tomography, heart rate variability and other methods. We propose an alternative noninvasive method based on visual diagnostics (VD) supported by a custom developed tool (ComVis), which enables interactive visual analysis of large data sets by simultaneous local and global view, multiple coordinated views and advanced interaction. Different statistical characteristics and time series of ECG and respiration measurements from fifteen patients and twelve healthy controls have been analyzed using the ComVis tool. Heart beats were synchronized on well defined expiration moment and analyzed in time-domain. The shape and the phase of the average heart rate changes near to the moment of expiration have been found, by interactive visual analysis, as new diagnostic tools for the investigation of transplanted heart recovery.

Download link: http://www.irb.hr/hr/cir/rep/projects/cenvis/papers/Visual_Analysis_of_Heart_Reinervation_after_Transplantation.pdf/

Forum: http://www.irb.hr/hr/cir/cenvis./