Category Archives: Uncategorized

Insights into 5G Technology: Some Data TransmissionAspects

ZlatkaValkova-Jarvis, Viktor Stoynov

Abstract.5G networks are the next-generation of telecommunications services and are expected to meet users’ growing demands and quality requirements. Intelligent high-speed services call for more spectrumwhich, coupled with the continuously growing number of users,creates the need for a technological leap in their development. The concept of using the millimeter waveband for telecommunication needs inevitably results in the introduction of new technological solutions that are in harmony with the Gbits/sec data-rate transmission. This publication presents some of the main data transmission aspects of upcoming 5G telecommunications networks, the reasons for their development and the scientific issues arising.

Key words:MassiveMultiple-Input Multiple-Output (M-M1M0),Orthogonal Frequency Division Multiplexing (OFDM) technology, Full-Duplex, Millimeter wave (mmW) spectrum, 5G networks

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Search in Knowledge Base Represented with Semantic Graphs

Ventzislav Nikolov, StefanPanov

Abstract: This article presents methods for searching in semantic graphs / S-graphs/ used for formal representation of subject areas. Shown are opportunities to update the facts and relations in the semantics of the subject area with an emphasis on the requirement to preserve consistency, completeness of data and relations between them.

Keywords: Semantic networks, Classes and objects, Relation.

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Semantic Graphs for Knowledge Representation

Ventzislav Nikolov, Stefan Panov, Dimitar Pilev

Abstract: .The subject of this article is the formal presentation of knowledge in any subject area by using semantic networks and generalized relations that define its semantics. Introduced and used are notions for basic and dependent classes as well as basic and dependent objects as instances of the respective classes. A method for building a semantic network with specific instances of the defined classes on the basis of the presented semantics is discussed.

Keywords: Semantic networks, Classes and objects, Relation

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Software Supporting of Dental Labors

Ventzislav Nikolov, Stefan Panov, Dimitar Pilev

Abstract: The focus in this article is a software system for supporting activities in a dental clinic. Discussed are the objects in the subject area as well as their structure is exposed in view of the formal representation of the processes in the clinic. Described is the distribution of roles between the staff at the clinic besides functional relationships between them are defined.

Keywords: Database,ER-model, SQL-Server, dental clinic.

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Heterogeneous Biological Data Integration

Hristo Stoev

Abstract: Major challenge in the analysis of biological data is to propose an integrated and modern access to the progressively increasing amounts of data in multiple formats, and efficient algorithms for their processing. The paper examined the models for extraction and integration of large amount of biological data, as well as problems related to heterogeneity, distribution and compatibility of data. A conceptual architecture for integrating of distributed biological data based on service-oriented architecture is proposed.

Key words: biological database, data integration, heterogeneous, service oriented architecture.

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Interactive Visualization — Problems and Approaches

Ani Dimitrova

Abstract: The visualization of large datasets at interactive rates has been a great challenge for decades. As a result a lot of approaches have been used and a lot of techniques have been developed. The presented article tries to summarize the main approaches. First, a definition of the term “large data” is given and the need of out-of-core techniques is explained. Then, the approach known as Spatialization is discussed. The article focuses on the meaning and the types of the so called Level Of Details (LODs) as well as on the caching and prefetching using the real interactive visualization system, called iWalk for illustrations. In the end some additional techniques for graphics pipeline optimization are mentioned.
Key words: large dataset, out-of-core visualization, spatial data structures, model simplification, level of detail, cashing and prefetching.

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Architecture Optimized for Enterprise Data Warehouse for Order Management and their Transactions

Ivan Stankov

Abstract: Proposed a new conceptual model and architecture for enterprise data warehouse for management of orders and their transactions. A comparison is made between summary data mart bus architecture with linked dimensional data marts and proposed an optimized architecture. Graphical representation of results.

Key words: Enterprise Data Warehouse for order management and their transactions. Optimizing an architecture.

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Scientific Software for CT Image Segmentation —A Comparative Study

Elena Kalcheva – Yovkova, Mariana Goranova

Abstract: The paper describes a state-of-art of recently available scientific software solutions in the area of segmentation and visualization of computer tomography images. Several software solutions are compared according to the available segmentation approaches, system flexibility and extensibility, maintaining pipeline processing and new algorithms evaluation. Also the architecture and supported data types are revised.
Key words: images processing, segmentation approaches, software solutions

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Obtaining G-buffers for Non-Photorealistic Rendering: Software Tools and Procedure

Virginiya Dimitrova

Abstract: One of the most important issues in Non-Photorealistic Rendering (NPR) is the encoding of 3D information into 2D data structures, called geometric buffers or, for short, G-buffers. The current article presents a fast and easy procedure to obtain different kinds of G-buffers. The procedure is based on the programming tools supported by the 3ds max such as data structures, classes, functions and software components. First, a brief description of G-buffers — terminology, kinds and applications in the field of NPR – is offered. Then, different types of geometric information about the scene are analyzed together with the approaches to encode this information on pixel basis (in bitmaps). The main focus of the article is on the question how can we generate G-buffers from a 3D scene and store them for subsequent exploration and processing in NPR.
Key words: 2D data structures, 3D geometric information, 3ds max, bitmap, G-buffer, MaxScript, non-photorealistic rendering

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Novel Modified Electromagnetic Bandgap Structures with Enhanced Bandstop Capabilities Based on Jerusalem Cross

Evgeniy Markov, Marin Nedelchev

Abstract: This paper proposes two novel EBG structures with enhanced bandstop capabilities, based on the modified Jerusalem Cross. They are initiated with physical alterations of the initial JC unit cell dividing the cross lines into coupled lines and addition of an electrically small patch presenting a capacitance in the center of the unit cell. Full wave FDTD analysis of infinite 2D periodic structures is performed and their bandgap characteristics are shown. It is shown that the stopband of the proposed structures is wider that the original Jerusalem Cross.

Key words: EBG design, bandstop, bandpass, periodic structures, transmission line analysis, full wave analysis, FDTD, surface waves

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