Volodymyr Mosorov

Modelling of dynamic experiments in MCNP5 environment

The design of radiation measurement systems includes a modelling phase which ascertains the best 3D geometry for a projected gauge. To simulate measured counts by a detector, the widely-used rigorous phenomenological model is used. However, this model does not consider possible source or/and detector movement during a measurement interval. Therefore, the phenomenological model has been successfully modified in order to consider such a displacement during the time sampling interval in dynamic experiments. To validate the proposed model, a simple radiation system was accurately implemented in the MCNP5 code. The experiments confirmed the accuracy of the proposed model.

The Lambert-Beer law in time domain form and its application

The majority of current radioisotope gauges utilize measurements of intensity for a chosen sampling time interval using a detector. Such an approach has several disadvantages: temporal resolution of the gauge is fixed and the accuracy of the measurements is not the same for different count rate. The solution can be the use of a stronger radioactive source, but it will be conflicted with ALARA (As Low As Reasonably Achievable) principle. Therefore, the article presents an alternative approach which is based on modified Lambert-Beer law. The basis of the approach is the registration of time intervals instead of the registration of counts. It allows to increase the temporal resolution of a gauge without the necessity of using a stronger radioactive source and the accuracy of the measurements will not depend on count rate.

SWIRL FLOW ANALYSIS BASED ON ELECTRICAL CAPACITANCE TOMOGRAPHY

This paper describes an application of dual-plane Electrical Capacitance Tomography (ECT) system for gas-solid swirl flow measuremetns. The angular component of the velocity in the pipes cross section was calculated. The angular velocity was determined based on tomographic data sets obtained from the physical model and also simulated data sets of the swirl flow phenomena. Analysis of material concentration changes in time, with the aid of sequences of 2D reconstruction images, allowed to swirling flow, angular velocity vectors to be successfully evaluated.

An iterative position reconstruction algorithm for radioactive particle techniques

The Computer Automated Radioactive Particle Tracking (CARPT) technique is widely used to monitor the motion of the flow inside a reactor. Usually a single radioactive particle that is neutrally buoyant with respect to the phase is used as a tracker. The particle moves inside the volume of interest and its positions are determined by an array of scintillation detectors counting incoming photons. Well-known reconstruction algorithms have been traditionally used to map measured counts into the particle position coordinates by solving a minimisation problem between measured events and calibration data. However, these algorithms have serious drawbacks. Their accuracy is determined by resolution of a calibration grid, which results in low accuracy measurements in cases where the measurement interval is short. The article presents an original algorithm for reconstruction of the trace position. The reconstruction procedure calculates iteratively the trace position of the specified calibration data. The results of the simulations based on the MCNP5 package showed that compared with results obtained using the classical approach, the accuracy of the reconstruction position is increased by 46% for low noise counts and 38% for high noise counts. The technique can successfully be applied to monitor the motion of a radioactive tracer in a reactor.

MODIFIED, COMPLEMENTED TAXONOMY OF FAULTS IN FAULT-TOLERANT REAL-TIME SYSTEMS

This paper presents the main definitions relating to dependability. Basic definitions including reliability, security, maintainability, etc. are described first. They are then supplemented by additional definitions, which address to the threats of dependability (faults, errors, failures). Overlapping dependability standards, renumbering and integration can cause uncertainty when using of a certain definition. For this purpose, authors present complemented fault taxonomy for fault-tolerant real-time systems to eliminate inconsistencies and to unify existing fault taxonomies.

THE APPLICATION OF REDUNDANCY IN LEACH PROTOCOL

Nowadays wireless sensor networks have gained much popularity due to their flexibility. This progress has enabled the use of sensor nodes on an unprecedented scale and opened new opportunities for the so-called ubiquitous computerization. The total freedom of nodes distribution within the wireless sensor network (WSN), where the wireless characteristic is one of the greatest advantages of WSN, implies its greatest weaknesses. To overcome this challenge specialized routing protocols, such as many different version of LEACH, were ushered in so as to make effective use of the energy of the nodes themselves. This article aims to show the functioning of a new author’s solution, called IIS-LEACH, which uses redundancy as a basic element in increasing the reliability of WSN networks.

COMPARISON OVERVIEW OF AN ACTIVE FINGERPRINTING APPLICATION OF THE SECOND AND THE THIRD LAYER OF TCP/IP STACK

Nowadays, computer networks have become as popular as telephone networks fifteen years ago and by the year they are playing ever more important functions in human life. Not only they have created huge opportunities in many areas of life, facilitating communications or obtaining information, but also have provided online entertainment as well. The invention, originally developed for military purposes in one of the darkest periods of human civilization, has become the greatest discovery of the twentieth century, connecting millions of people around the world into one big community. Whatever the differences in size or devices used, a computer network can be defined as a combination of terminal devices, transmission medium, intermediate communication devices and network software (network area). Currently, anyone can build their own network or join the largest of them - the Internet - via a local Internet provider. Unfortunately, the Internet is not only a virtually unlimited source of information, entertainment, communication, and work. Alongside its positive aspects and conveniences it poses numerous risks to uninformed users. This publication aims to cast light on the aspects of the method of sampling operating systems security of network computers, i.e. active fingerprinting of the data link layer and Internet TCP/IP stack layer.

THE APPLICATION OF SENSOR NETWORKS WITHIN MOBILE CELL NETWORKS

Mobile devices such as mobile phones are getting increasingly popular by the year. Currently, most users cannot imagine doing without these devices that support our daily lives. Using them, however, entails a certain drawback, namely having to conclude an agreement with the mobile network operator, where the user undertakes to operate the device in keeping with the set rules and pay fixed amounts for the communications service provided by the operator. The authors’ overarching idea is both to reduce the costs of using mobile phones and achieves total independence from the mobile operator. To achieve this goal they propose a communications system that omits the mobile network operator’s infrastructure using methods taken from sensor networks. With the technological advancements it is now possible to manufacture devices whose size is in the order of centimetres. This enables the use of sensor nodes on an unprecedented scale and opens new opportunities even for a private user. Initially, sensor networks were wired solutions. The development of wireless and data processing technologies has helped sensor devices to take over a larger area of research. The purpose of this paper is to present the concept proposal of a free and reliable mobile network

Development of a stopping rule of clustering performance by using the connected acyclic graph

In this article the technique of the analysis of a stopping rule for the data preclustering algorithm without the prior information about the number of clusters with the use of a connected acyclic graph is introduced. The connected acyclic graph (tree) makes it possible to represent the interconnection between the objects in input data. The stopping rule allows a halt at the some step assuming that further clusterization will not cause finding new clusters. The core of the analysis was the application of the preclustering algorithm and the stopping rule to the series of input data which were represented by sample cases of input data. Sample cases were input data with normal distribution law which belonged either to a single group or to many groups. The analysis has shown the advantages of the stopping rule for the data preclustering algorithm.