Abstract: In this paper, the basic Narrowband Interference Suppression methods and algorithms in Single Input Single Output (SISO) digital Orthogonal Frequency Division Multiplexing (OFDM/DMT) communication systems are considered. The overviewed methods are applicable for both wireless OFDM and wire-line DSL DMT communication systems.
Key words: NBI, RFI, OFDM, DMT, DSL, Digital Communications, Digital Filters.
Abstract: Opening nefrvor/‹ interfaces allows enterpr/se applications to access communication functions in public networks. The paper presents a research› on capabilities for open access to ‹/ser data manapemenf through application programming interfaces. The requirements for open access to data stored in user profile server dep/oyed in the network are analyzed. An approach to design of application programming interfaces for user data manage/r›en/ is s‹/gges/ed. Functional mapping of interface reel/›ods onto ne/vv’or/‹ control protocol messages is studied. L/ser profile service data model is suggested. A use case is considered.
Key words: Open Service Access, Application Programming Interfaces, Generic Profile,Data Convergence, Internet Protocol Multimedia Subsystem
Stoicho Stoichev, Svetlana Marinova
Abstract: ’ The paper investigates the problem of parallel search by multiple attributes in an information system, designed for shared-memory parallel arch//ec/‹/res. Searching by multiple a//ribu/es is a common operation in databases and applying parallel search algorithms can acce/erate the execution in large databases. The existing para//e/ search algorithms based on multiple a//rid‹/fes are designed mainly for dis/ribr/fed-memory systems. We propose three new parallel algorithms for searching by two attributes, de/erm/ne theoretically their lime complexity and evaluate experimentally their performance on a multi-core processor. The algorithms are applicable for searching an array of records, sorted with a para//e/ algorithm for bucket sort. T/›e experiments show that the proposed parallel algorithms achieve speedr/p in most of the cases compared to a sequential searc/› algorithm. T/›e parallel algorithms based on bucket sort can acce/era/e significantly //›e searc/› in situations of unsuccessful search and key distributions, c/ose /o the uniform distribution. Based on the conducted experiments, we make recommendations for improvements of the parallel searc/› algorithms that are subject of a future work.
Key words: Algorithm, database, information sysfem, multi-core, multiprocessor, parallel, query, search
Ludmila Stoyanova, Daniela Minkovska
Abstract: ’This paper reveals some problems of the education in Informatics at Universities for Mechanical engineering faculties. The curricula content has been discussed and compared with the needs o/ the students’ further study at the Un!versity and their future work. An analysis of studied programming languages in Bulgaria and in many countries in Europe, North America and Asia has been made in connection with the further professional needs of the students. Additionally the res‹//is of students’ attitude towards f/›e programming languages have been analyzed. At //›e end conclusions have been made for the temporary requirements towards the programming language for mechanical engineering faculties at the Technical University.
Key words: education, informatics, mechanical engineering, programming language
Dimityr Stoimenov, Philip Petrov
Abstract: “ A system for development, installation and practical testing of control of car electronic modules through voice commands is presented. The system is capable of having configuration for different car models with different CAN network specifications. There is an intuitive and easy to use user interface with //exib/e navigation. The system is presented and defended as bachelor’s thesis in Technical University — Sofia, in Faculty of Compr/ter Systems and Technologies in 2010.
Key words: voice commands, voice control, cars, automobiles, CAN network, software
Abstract: ‘ The paper era/rra/es the main challenges of videoconferencing for e//ecfive business support. Description ot functionalities of electronic conferencing systems is made and comparaf/ve analysis o/ I/›e most famous e-conferencing systems is done. End-user products finding on the market are presented according to the dynamics of deve/opmenf of these systems and fast increasing of //›e interest and implementations.
Key words: electronic conferencing, videoconferencing, telepresence.
Haralambi Haralambiev, Stanimir Boichev, Milena Lazarova, Ognyan Nakov
Abstract: ’ The paper presents the problems of software visualization of complex information systems. Based on I/›e research analyses and definition of the requirements for the visualization system a concept for interactive s/at›c software visualization was developed in which static software analysis to be combined with filtering, clustering and the possibility of user inferacfion fo obtain a visualization that supports the understanding and the orientation in the software structure.
Key words: software visualization, visualization tools, interactive visualization, static visualization
Daniela Gotseva, Veska Gancheva
Abstract: ” The investigations presented in this paper, are a/med to optimization of database that are used for storing data using OLAP cubes. the possibilities for optimization using views and indexes arc presented. Solutions for query optimization using storecl procedures are supges/ed.
Key words: database, database se/ver, index, query, optimization, OLAP, stored procedures.
Boncho Aleksandrov, Nina Sinjagina, Petko Kotchevski
Abstract: In the present paper different characteristics of Shamir’s method for secre/ reconstruction and sharing are analyzed. A method for shared storage and reconstruction of secre/ information, based on the residue theorem, is proposed. By using the features of the resid//e theorem, some of the shortcomings of Shamir’s scheme have been eliminated. The proposed method makes it possible to identify the cases in which the shared secret has been incorrectly reconstructed
Key words: secret sharing, data profection, user identification.
Plamenka Borovska, Veska Gancheva, Ivailo Georgiev
Abstract: The effective comparison of biological data sequences is an important and a challenging task in bioinformatics. The process itself is a way of arranging DNA, RNA or protein sequences in order /o identify similar areas that may have a consequence of functional, structural or evolutionary re/a/ions between them. Smi//›-Waterman algorithm, based on dynamic programming has become
//›e most fundamental in bioinformatics. T/›e goal o I this paper is to inves/igafe the efficiency of
parallel multithreaded implementation based on Smith-Waterman algorithm. Performance parameters have been estimated by the experiments using various data sets and BLOSUM matrixes.
Key words: alignment, biological sequences, parallel algorithms, Smith- Waterman.