Monthly Archives: November 2013

Remote Control System for the Environmental Situation Around Large Industrial and Energy Complexes

Emil Altimirski

Abstract: The described remote control system for the environmental situation around large industrial and energy complexes – plants, factories, power plants, etc. being developed in the Department of Telecommunications of the Technical University in Sofia The system is composed of several hierarchical levels – sensors and actuators, peripheral controllers with communication module, dispatcher station and the user interface. Equipment are described; the main modes of operation; communication methods and tools; the studies, observations and calculations for the selection of the parameters of the subsystems and the implementation of the system.

Key words: environmental situation, remote control system

Download Article

Web Services for Session-based Instant Messaging

Evelina Pencheva

Abstract: Instant messaging is a service that allows exchange of different types of messages including multimedia in close to real time. Parlay X Web Services provide an easy way for application developers to program communication network resources using application programming interfaces instead of complex control protocols. The paper studies deployment considerations of third party control on session-based instant messaging through Parlay X Audio call interfaces in all Internet protocol based multimedia networks. Functional mapping of Web Service interface operations onto messages of communication protocols used for control and provisioning of session-based instant messaging is proposed. The behavior of Parlay X gateway is formally described and verified.

Key words: Third party control, session management, media transport, finite state machines
Download Article

Internet Access to ZigBee-Based Sensor Network

Milen Todorov, Boyanka Nikolova, Georgi Nikolov

Abstract: IEEE 802.15.4 is the first global standard for compatible interconnection for data communication devices using low-data-rate, low-power, and low-complexity short-range radio frequency transmissions in a wireless personal area network (WPANs). ZigBee is a protocol specification in conjunction with IEEE 802.15.4 standardization. In this paper are presented network analysis of sensor network and interconnection between ZigBee network and remote networks via Internet. The interconnection is achieved using XBee Internet Gateway for the Digi ConnectPort. The gateway allows to connect the Digi’s XBee radios from a WPAN to Internet via Ethernet, cellular data and satellite links.

Key words: Arduino, ConnectPort, IEEE 802.15.4, Perytons, XBee, XIG, ZigBee.
Download Article

Rectangular Object Detection based on CLAHE and Hough Transform

Veska Georgieva, Georgi Dimov

Abstract: The problem of detecting rectangular structures in images or video sequences arises in many applications. This paper proposes an integrated approach for rectangular detection based on Contrast Limited Adaptive Histogram Equalization (CLAHE) for observing a better contrast in RGB images, following by median filtration and Canny edge detection to suppress some kind of noise and most possible false edges, and modification of Hough Transform (HT). Peaks of the Hough image (which correspond to line segments) are extracted, and a rectangle is detected when four extracted peaks satisfy certain geometric conditions. Implementation results are given to demonstrate the application of this approach in real images.

Key words: Rectangular detection, CLAHE, Canny edge detection, Hough Transform`”Bvpavi re Windows arsope-re macrpoilorre, 3a as aKTI Ifirldnime
Download Article

Web Services Management Using Business Processes

Anastasios Profitis

Abstract: Increasing information on the Internet leads to increasing need to automate some aspects of web services, like discovery, selection and service composition. The main goal of this paper is to propose software architecture for management of Web services through a series of business processes, which allows flexibility in the construction of the composition of web services by selecting the appropriate services and automatically update them with new ones. The core of the proposed software architecture is a component SPARQL for data retrieval from semantic repositories as well as composition construction as collections of objects.

Key words: business processes, workflows, semantic web services, SPARQL.

Download Article

An Application of Cocoa Bindings and MVC Technology by Designing of a User Interface with Data Bases

Ventzislav Nikolov, Dimitar Pilev

Abstract: The subject of discussion of this article is the MVC paradigm, Cocoa-binding technology and their application in a financial software system. A communication with the data base PostgreSOL- tables via the model is described, too.

Keywords: MVC, Cocoa-binding, Objective C programming, KVO

Download Article

Interaction Between Subject Area Model, Student Model and Planning Activities in Learning Process

Ventzislav Nikolov, Stefan Panov

Abstract: The subject of the article is the knowledge models on which is based a system for generating teaching courses. As a main model which represents the subject area knowledge and semantic dependencies in it is accepted a tree. For estimating the student level of knowledge and skills the tree structure by using semantic dependencies will be transformed in a directed graph. The purpose of navigation in the graph is to obtain the knowledge incompleteness of the student. The tree knowledge structure of the subject area and the resulting knowledge incompleteness are a base to derive the learning history, testing model and student model.

Keywords: machine learning, directed graph, learning tree, student model.
Download Article

Evaluation of Instruction Dependencies in Multithreaded Application Executed on Heterogeneous Architectures

Maria Marinova, Dimitar Garnevski, Vladimir Lazarov

Abstract: Modern heterogeneous architectures include advanced computing devices with great multi-threading capabilities. Unfortunately not all applications utilize all these capabilities due to the specific or complexity of algorithms. One of the obstacles which come from the natural execution of algorithms is “data dependencies”. The main objective of this paper is to provide results from research in area of data dependencies in multi-threaded parallel applications and show influence of these dependencies on the particular applications.

Key words: data dependencies, multi-threaded applications, heterogeneous architectures, GPU.
Download Article

Surreptitious Forwarding of the Digital Signature

Asen Hadzhitinev

Abstract: Most users and application programmers prefer to think about encryption by analogy with symmetric encryption – a kind of secret code and shared secret, but the digital signature schemes have significantly different semantics. In this paper, we will review some naive Sign and Encrypt scheme implementations of e-mail encryption, in the context of modern standards: S/MIME, PKCS # 7, PGP, OpenPGP, PEM, MOSS and Secure XML, and we will offer a few simple adjustments eliminating the possibility of tampering, by creating a relationship between inner and outer layer of cryptographic message.

Key words: e-mail, cryptography, digital signature, cryptography standards, S/MIME, PKCS#7, PGP, OpenPGP, PEM, MOSS, Secure XML, sign and encrypt crypto scheme, errors, implementation.

Download Article

Using Regular Expressions for Processing of XSD

Vaylo Atanassov, Velko Iltchev

Abstract: The present paper offers a method for XML validation with XSD files. The XSD files are translated to regular expressions. In contrast with standard regular expressions, in this case are necessary lower and upper limits for looping. New structures are introduced when implementing the validation process. An example of various regular expressions and the corresponding tables are given.

Key words: XML, XSD, regular expressions, finite automata. 
Download Article