Pencho Marinov

Analytical expression of O+H+ ion transition surface for use in IRI

A global surface of O+H+ transition level is constructed, based on published data from OGO-6, Intercosmos-2, Alouette-1, ISS-b, and TAIYO satellites. This surface covers ±60° dipole latitude, all longitudes, two levels of solar activity, summer and winter solstices, and 00 and 12 hours local time. The surface is used as input data to a mathematical model which calculates transition levels in 5-dimensional space: sunspot number (R), month (M), local time (LT), dipole latitude (DL), and longitude (LONG). This model is based on a generalized multivariable polynomial, using a system of linearly independent functions. Model transition levels are compared with averaged data from AE-E and AE-C, as well as rocket measurements from Vertical-6 and Vertical-10. The obtained analytical expression can be directly used in IRI.

Ant Algorithm for Optimal Sensor Deployment

Telecommunications is a general term for a vast array of technologies that send information over distances. Mobile phones, land lines, satellite phones and voice over Internet protocol are all telephony technologies - just one field of telecommunications. Radio, television and networks are a few more examples of telecommunication. Nowadays, the trend in telecommunication networks is having highly decentralized, multi-node networks. From small, geographically close, size-limited local area networks the evolution has led to the huge worldwide Internet. In this context Wireless Sensor Networks (WSN) have recently become a hot topic in research. When deploying a WSN, the positioning of the sensor nodes becomes one of the major concerns. One of the objectives is to achieve full coverage of the terrain (sensor field). Another objectives are also to use a minimum number of sensor nodes and to keep the connectivity of the network. In this paper we address a WSN deployment problem in which full coverage and connectivity are treated as constraints, while objective function is the number of the sensors. To solve it we propose Ant Colony Optimization (ACO) algorithm.

An approximation of the height of the O+ - H+ transition level for use in IRI

Abstract A set of data including over 1400 transition level (TL) encounters of the OGO-6 satellite is used to construct analytical presentations of this altitude upon dip-latitude and longitude. The formula represents the TL variation between ± 50° dip-latitude and 20 h and 04 h local time interval. The data were obtained in the high solar activity period in 1969 and 1970.

Intense current structures during low geomagnetic activity and their relation to small-scale magnetic perturbations seen by the Intercosmos Bulgaria-1300

Abstract This paper deals with the initial observational data on the field-aligned currents (FAC) and the small-scale transverse magnetic perturbations (SSTMD) in the cusp region obtained from the magnetometer on board the Intercosmos Bulgaria-1300 satellite. The magnetic field has been investigated by a high accuracy flux-gate magnetometer, IMAP, designed in the Central Laboratory for Space Research (CLSR), Sofia. For low geomagnetic activity 10 meridional passes (September–December 1981) have been examined. Intense FAC are observed in the noon sector of the summer auroral region. SSTMD are superimposed on a weak cusp current as a perturbation in the prenoon sector of the winter auroral region.

Intercriteria analysis of calorimetric data of blood serum proteome

BACKGROUND Biological microcalorimetry has entered into a phase where its potential for disease diagnostics is readily recognized. A wide variety of oncological and immunological disorders have been characterized by differential scanning calorimetry (DSC) and characteristic thermodynamic profiles were reported. Now the challenge before DSC is not the experimental data collection but the development of analysis protocols for reliable data stratification/classification and discrimination of disease specific features (calorimetric markers). METHODS In this work we apply InterCriteria Analysis (ICA) approach combined with Pearsons and Spearmans correlation analysis to a large dataset of calorimetric and biochemical parameters derived for the serum proteome of patients diagnosed with multiple myeloma (MM). RESULTS We have identified intercriteria dependences that are general for the various types of MM and thus can be regarded as a characteristic of this largely heterogeneous disease: strong contribution of the monoclonal (M) protein concentration to the excess heat capacity of the immunoglobulins-assigned thermal transition; shift of the albumin assigned calorimetric transition to allocation where it overlaps with the globulins assigned transition and strong shift of the globulins assigned transition temperature attributable to M proteins conformational changes. CONCLUSIONS Our data justify the applicability of ICA for deciphering of the complex thermodynamic behavior of the MM blood serum proteome. GENERAL SIGNIFICANCE The applied approach is suitable for more general application in the analysis of biocalorimetric data since it can help identify the biological relevance of the distinguished thermodynamic features observed for variety of diseases.

Real time 3-D electron density reconstruction over Europe by using TaD profiler

The TaD (Topside Sounder Model (TSM)-assisted Digisonde) profiler, developed on the basis of the Topside Sounder Model (TSM), provides vertical electron density profiles (EDP) over Digisondes from the bottomside ionosphere up to Global Navigation Satellite Systems (GNSS) orbit heights. TaD EDP uses the Digisonde bottomside profile and extends it above the F2 layer peak, representing O+ distribution by α-Chapman formula and H+ distribution by a single exponent. Topside scale height HT and transition height hT are taken from TSM, while the plasmasphere scale height Hp is defined as a function of HT. All profile parameters are adjusted to the current conditions comparing the profile integral with the GNSS vertical total electron content (TEC) retrieved from the European Reference Frame (EUREF) maps. To expand to three dimensions (3-D), European maps of foF2 and hmF2 are produced, based on Digisonde data, with spatial resolution 1°×1° in latitude and longitude, and TaD profiles are calculated at each grid node. Electron density (ED) at any point of the 3-D space is obtained by linear interpolation of TaD parameters between neighbor nodes. Samples of two dimensional (2-D) electron density distribution (EDD) at different cross sections of the 3-D space between 200 km and 1150 km over the mapping area are presented, along with distributions of the electron density along various raypaths of GNSS signals. The modeled 3-D EDD is compared with vertical (vTEC) and slant (sTEC) TEC parameters calculated from individual GNSS receivers. The model error (relative deviation of model from the data), based on 6780 data values, is 10% for sTEC and 6% for vTEC.

Multi-objective ACO algorithm for WSN layout: performance according to number of ants

Wireless sensor networks monitor physical or environmental conditions. One of the key objectives during their deployment is full coverage of the monitoring region with a minimal number of sensors and minimised energy consumption of the network. This problem is hard, from the computational point of view. Thus, the most appropriate approach to solve it is application of some metaheuristics. In this paper we apply multi-objective ant colony optimisation to solve this important telecommunication problem. The number of the agents ants is one of the important algorithm parameters in the ant colony optimisation metaheuristics. The needed computational resources for algorithm performance depends on number of ants. When the number of ants increases the computational time and used memory increase proportionally. Thus it is important to find the optimal number of agents needed to achieve good solutions with minimal computational resources. Therefore, the aim of the presented work is to study the influence of the number of ants on the algorithm performance.

Optimal solvers for linear systems with fractional powers of sparse SPD matrices: Optimal Solvers for Linear Systems with Fractional Powers of Sparse SPD Matrices

In this paper we consider efficient algorithms for solving the algebraic equation

MULTI-OBJECTIVE ANT ALGORITHM FOR WIRELESS SENSOR NETWORK POSITIONING

{\mathcal A}^\alpha {\bf u}={\bf f}

Intuitionistic fuzzy estimation of the ant colony optimization starting points

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