Dimitar Karastoyanov

InterCriteria Decision Making Approach to EU Member States Competitiveness Analysis: Trend Analysis

In this paper, we continue our investigations of the newly developed InterCriteria Decision Making (ICDM) approach with considerations about the more appropriate choice of the employed intuitionistic fuzzy threshold values. In theoretical aspect, our aim is to identify the relations between the thresholds of inclusion of new elements to the set of strictly correlating criteria and the numbers of correlating pairs of criteria thus formed. We illustrate the findings with data extracted from the World Economic Forum’s Global Competitiveness Reports for the years 2008–2009 to 2013–2014 for the current 28 Member States of the European Union. The study of the findings from the considered six-year period involves trend analysis and computation of two approximating functions: a linear function and a polynomial function of 6th order. The per-year trend analysis of each of the 12 criteria, called ‘pillars of competitiveness’ in the WEF’s GCR methodology, gives an opportunity to prognosticate their values for the forthcoming year 2014–2015.

InterCriteria Decision Making Approach for Iron Powder Briquetting

In this paper, we present approach, called ‘InterCriteria Decision Making’ that utilizes the apparatus of index matrices and intuitionistic fuzzy sets which from an existing multiobject multicriteria evaluation table generates a new table that contains estimations of the pairwise relations among the set of evaluating criteria. In the presented paper for the analysis purposes we have used experimental results of impact briquetting of iron powder. In this study we illustrate the application of the one original methodology to the data achieved for the following parameters distance, speed and acceleration of the impacting bodies. The research and the obtained results will show relations between the briquetting process parameters which will lead to increase in its efficiency.

Exploiting a Graphical Braille Display for Art Masterpieces

A new graphical Braille display is presented. Its use, social value and advantages are discussed. In particular is developed an approach allowing objects of cultural and historical heritage to be presented in an intuitive and accessible way to low-sighted or blind people.

Innovative Graphical Braille Screen for Visually Impaired People

The graphical interfaces based on visual representation and direct manipulation of objects made the adequate use of computers quite difficult for people with reduced sight. Within the European Union, the problem with the access of blind people to computer resources is quite pressing. A new type graphical Braille screen is developed. The Braille screen is a matrix with linear electromagnetic micro drives and non magnetic needles, passing trough the axes of the electromagnets. Over the electromagnets is mounted a grid with holes. The needles go through the holes and move up pimples. The visually impaired peoples feel them tactile way and can adopt symbols and graphics. Permanent magnet linear actuator intended for driving a needle in Braille screen has been proposed and optimized. Finite element analysis, response surface methodology and design of experiments have been employed for the optimization. The influence of different parameters of the construction of the developed permanent magnet linear electromagnetic actuator for driving a needle in a Braille screen is also studied. Static force characteristics of the actuator for driving a needle in Braille screen are presented. Using the graphical Braille screen, we can present symbols and simple graphics—Windows icons for example. The results of experiments for high speed moving of Braille needles using linear electromagnetic micro drive are presented. The experiments were conducted in the laboratory “Smart lab” with using of high speed camera NAC Memrecam. The international for Bulgarian patent application is presented as follows: Braille Screen—WIPO Patent Application, No P C T/B G 2014/000038, October 24, 2014; Braille Screen—Bulgarian Patent Application, No 111638, November 29, 2013

InterCriteria Decision Making Approach for Metal Chips Briquetting

In the presented paper for the analysis purposes we have used experimental results of impact briquetting of grey cast iron chips. The presented multicriteria decision making method is based on two fundamental concepts: intuitionistic fuzzy sets and index matrices. We have named it ‘InterCriteria’ decision making approach, which utilizes the apparatus of index matrices and intuitionistic fuzzy sets takes an existing multiobject multicriteria evaluation table and generates a new table that contains estimations of the pairwise relations among the set of evaluating criteria. Our goal is to increase the efficiency of the process of briquetting metal chips with good density and quality.

Control system for “controlled impact” laboratory device

The “controlled impact” laboratory device is developed in Technical University of Sofia. The acceleration of impact bodies is realized by cold rocket engine, which is operated with compressed air. The control system of the device ensure impact velocity up to 8 m/s, and measurement of impact parameters - path, velocity, acceleration. The parameters of the control system and there accuracy are investigated.

New type electromagnetic drive for Braille screen

The graphical interfaces based on visual representation and direct manipulation of objects made the adequate use of computers quite difficult for people with reduced sight. Within the European Union, the problem with the access of blind people to computer resources is quite pressing. The main scientific aim here is: a concept for development, design and manufacture prototype of combined tactile-voice interface facilitating and allowing visually impaired people work with computers regardless of the user interface or operation system and oriented to graphical surfaces. Static force characteristics of recently developed permanent magnet linear actuator for driving a needle in Braille screen are presented.

Computer system for navigating a mobile robot

In this paper a fuzzy and communication system for managing and controlling the basic movements of a mobile robot is proposed. Several ultrasound and infrared sensors are installed on the robot and the collected data is operated with the means of fuzzy logic and thus decisions for the robot route are made. This intelligent system is created to navigate the mobile robot indoors in an unknown environment. The application areas of the robot are for embedded and mobile device, guiding of visual impaired people, mobile vehicle in technological lines, etc.∗

Art Masterpieces Accessibility for Blind and Visually Impaired People

A new representation of content for haptic exploration of two-dimensional pictorial art masterpieces is presented. To realize a “tactile image”, pictures must be simplified and converted to a bas-relief with distinct and logically homogeneous areas, so that each segment can convey the original content in an intelligible way. Pictures must be digitized, modified, adapted and reconstructed as 3D models that are finally processed by a 3D printer to get an object analyzable through fingertips. We assess the quality and efficiency of the proposed solution through a cooperation with the Italian Union of Blind and Visually Impaired People. The resulting representations were implemented in two different events, gathering visitors’ comments. Remarks obtained during the exhibition in Pavia in 2015 led to a version of a tactile image that is now shown in Milan, at the Pinacoteca di Brera, beside the original masterpiece. The collected comments confirm that the approach is appreciated.

Wear resistance of WC/Co HVOF-coatings and galvanic Cr coatings modified by diamond nanoparticles

The efforts in the recent 20 years are related to search of ecological solutions in the tribotechnologies for the replacement of galvanic Cr coatings in the contact systems operating under extreme conditions: abrasion, erosion, cavitation, corrosion, shock and vibration loads. One of the solutions is in the composite coatings deposited by high velocity gas-flame process (HVOF). The present paper presents comparative study results for mechanical and tribological characteristics of galvanic Cr coatings without nanoparticles, galvanic Cr coatings modified by diamond nanoparticles NDDS of various concentration 0.6; 10; 15 и 20% obtained under three technological regimes, and composite WC-12Co coating. Comparative results about hardness, wear, wear resistance and friction coefficient are obtained for galvanic Cr-NDDS and WC-12Co coatings operating at equal friction conditions of dry friction on abrasive surface. The WC-12Co coating shows 5.4 to 7 times higher wear resistance compared to the galvanic Cr-NDDS coatings.