Pournaras A.,Technical University of Gabrovo
Journal of Engineering Science and Technology Review | Year: 2017
The contemporary classic theory of gearing is realized through the instrument needed for production of the toothed wheels of the gear. By means of the proposed relationships in the present report, it is proposed that all instrumental limits are eliminated and that free geometric synthesis to realized by observing the principles of Olivier and basic theorem of Zalgaller-Litvin. The work compares both synthesis methods - the classic and the contemporary one - while discovering some not yet used opportunities for geometric synthesis of involute cylindrical gears in accordance with preset qualitative parameters. © 2017 Eastern Macedonia and Thrace Institute of Technology.
Madzharov N.,Technical University of Gabrovo
Journal of Engineering Science and Technology Review | Year: 2016
The technical problems treated in the present paper are related to the development of a specific high - frequency power supplies for different applications - induction heating, contactless power transfer systems, ultrasonic devices and etc. They are, in their nature, a hybrid between the achievements in modern microelectronic components - frequency capabilities and low commutational losses, and the latest trends in the development of power conversion circuit manifested in the use of adaptive energy circuits which always maintain the power constant and independent from the load changes [1, 2, 3]. Actually two circuits were investigated and are presented in this paper - a half-bridge circuit and a bridge one, the latter being claimed as a patent by the author. They have their own specific characteristics and in relation to this, specific areas of application determined mainly by their output voltages. © 2016 Eastern Macedonia and Thrace Institute of Technology. All rights reserved.
Ivanov R.,Technical University of Gabrovo
Journal of Ambient Intelligence and Smart Environments | Year: 2017
This article presents a Building Information Model (BIM), which describes the topology, geometry, and semantics of buildings; user preferences; and status of sensors deployed in the building. The aim is to propose an approach for developing a context-aware indoor navigation system, which assists blind and visually impaired people in unfamiliar large public buildings with complex horizontal and vertical connectivity. The proposed building data model aims to overcome the drawbacks of existing BIM-based Indoor Navigation Systems (INS). The innovation aspects of the proposed data model can be summarized as follows: 1)Abstract description of the hierarchy of building elements; 2)BIM is focused on indoor navigation. It allows one to extract information about the topology of a specified part of the building, which is used by an algorithm for coarse-to-fine path finding; 3)Provides rich semantic information on all building elements, objects and users located in the building; and 4)Provides all necessary information for obstacle (fixed and movable) avoidance. © 2017 - IOS Press and the authors. All rights reserved.
Sadinov S.M.,Technical University of Gabrovo
2017 40th International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2017 - Proceedings | Year: 2017
Recent theoretical studies of communication systems show much interest on high-level modulation, such as M-ary quadrature amplitude modulation (M-QAM), and most related works are based on the simulations. In this paper, a simulation model to study various M-ary QAM modulation techniques is proposed. The simulation model is implemented in Matlab/Simulink environment and BERTool in conjunction with the model is also used. Simulation for 64-QAM and 256-QAM modulation techniques is done. The effect of the phase noise on the constellation diagram for both M-QAMs is examined. The impact of changing the power of the input signal, phase noise and frequency offset on Bit Error Rate (BER) performance of 64-QAM and 256-QAM is also studied. The simulation results in terms of the constellation diagram and the BER curve under various conditions are presented and analyzed. © 2017 Croatian Society MIPRO.
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: GC.SST.2012.1-2. | Award Amount: 2.40M | Year: 2012
FastInCharge will last 36 months and be lead by a consortium of 9 partners (France, Spain, Greece, Bulgaria, Italia and Slovakia): 1 SME specialised in charging infrastructure for electric vehicles (DBT), 1 industrial group of automotive engineering (BATZ), 3 research organisations, specialists of contactless power, automotive engineering and energy management systems (Tecnalia, TU Gabrovo, NTU Athens), 1 end-user (Douai), 1 cluster (ACWS) , 1 SME in innovation management (EQY) and 1 OEM (CRF). The overall objective of FastInCharge is to foster the democratisation of electric vehicles in the urban environment by developing an easier and more comfortable charging solution which will enable to ease the EV use by the large public and facilitate their implementation in the urban grid. FastInCharges intention is to develop a cost-effective modular infrastructure offering a global solution for EV charging. Its success will boost research in the direction of dynamic charging solutions. The concept of FastInCharge is to create a highly performing inductive solution which will enable a 40 kW power transfer to the vehicles in two charging operational situations: one stationary and one on-route. The inductive technology developed will be integrated into: three different electric cars of different types (secondary charging block) and four charging stations, one stationary and three on-route (primary charging block). The full functional chain will be carefully scrutinised in order to ensure an optimal, safe and sustainable solution: battery charging, EV performance and safety, EV range, communication EV/Station, connection station to the grid, grid management and energy supply, intelligent coordinated systems. The programme consists in seven work packages: 1) Specifications, 2) Development of fast inductive charging infrastructure, 3) Development of integration solutions; 4) Prototyping and testing; 5) Demonstration, 6) Dissemination and Exploitation, 7) Management.
Stamova I.M.,Bourgas Free University |
Ilarionov R.,Technical University of Gabrovo
Computers and Mathematics with Applications | Year: 2010
In this paper, the problem of global exponential stability for cellular neural networks (CNNs) with time-varying delays and fixed moments of impulsive effect is studied. A new sufficient condition has been presented ensuring the global exponential stability of the equilibrium points by using piecewise continuous Lyapunov functions and the Razumikhin technique combined with Young's inequality. The results established here extend those given previously in the literature. Compared with the method of Lyapunov functionals as in most previous studies, our method is simpler and more effective for stability analysis. © 2010 Elsevier Ltd. All rights reserved.
Ivanov R.,Technical University of Gabrovo
Journal of Network and Computer Applications | Year: 2012
Outdoor navigation of visually impaired people most often is based on data from the GPS maps and Geographic Information Systems (GIS). Such systems cannot be used for navigation in the regions where there are not any GPS maps or the maps are not sufficiently precise and detailed. This article describes an algorithm for real-time GPS track simplification. The test results show that the proposed algorithm (RSTS) has efficiency similar to the Douglas-Peucker algorithm, which is regarded as the best for track simplification. The reduction of the number of points in different transportation modes, while keeping the shape of the route, is over 90%. The size of the file describing the track is reduced more than 30 times. The algorithm finds the critical points of the route. This allows for navigation along the track so conversion of track to route is not needed. The algorithm is part of a low cost and widely accessible Java 2 Mobile Edition (J2ME) application for navigation of visually impaired. © 2012 Elsevier Ltd.
Todorov T.D.,Technical University of Gabrovo
Computers and Mathematics with Applications | Year: 2015
The paper deals with a nonlinear second-order elliptic equation with Dirichlet boundary conditions. The nonlocal term involved in the strong problem essentially increases its complexity and the necessary total computational work. The existence and uniqueness of the weak solution is established. The nonlinear weak formulation is reduced to the minimization of a nonlinear functional. Finite element discretizations by Lagrangian finite elements are applied to obtain an approximate minimization problem. A two-point step size gradient method with an original steplength is used for finding approximate solutions of the problem under consideration. No line search is necessary in the new approach. The present method is computer implemented and tested on different triangulations. The test examples indicate that the method slightly depends on the initial guesses. © 2015 Elsevier Ltd.
Ivanov R.,Technical University of Gabrovo
Journal on Multimodal User Interfaces | Year: 2014
This article presents an Java-based mobile service that enables blind-environment interaction through voice-augmented objects. To make this possible, it is necessary to tag the object with an associated radio frequency identification and record its voice-based description. The blind users can later use the service to scan surrounding augmented objects and verbalize their identity and characteristics. We use a user centred design in order to guarantee the accessibility of the service for visually impaired and blind people. The required hardware is a near field communication-enabled mobile phone with built-in accelerometer. The client-side application does not require pushing any buttons, browsing any menus, or touching any screens to select and activate any of supported modes: registration, calibration, voice recording, physical object identification, delete voice recording(s), cloud-based file sync and share. Twelve visually impaired individuals (aged 31–84, 6 men and 6 women) have tested the service in two different scenarios: (1) a test based on comparison with a PenFriend labeling unit, and (2) a users’ experience test. The results show that selected tangible, multimodal interface (object touching, phone shaking and tilt, voice output) can be used very easily (58 %) or easily (33 %) by blind and visually impaired users who have had no previous experience with other mobile services. Most of participants from the test group agreed that the service could be useful for their daily activities. The service can be used both at home and in public buildings for voice description of objects such as food, medicines, books, clothes, cosmetics, CD/DVDs, rooms, etc. © 2014, OpenInterface Association.
Ivanov R.,Technical University of Gabrovo
ACM International Conference Proceeding Series | Year: 2013
In this paper we present the design, development and implementation of the pervasive learning system for children. The required hardware is a Near Field Communication (NFC)-enabled mobile phone with built-in accelerometer. Trainers (teachers or parents) describe the objects from the learning environment through their voice and associate this voice-based description to a specific object by using the radio frequency identification (RFID) tags. They are able to sync their audio recordings, to share and re-associate with their own RFID tags (clone) audio recordings of other trainers through Google App Engine cloud environment. Children can later use the service to scan surrounding augmented objects and verbalize their identity and characteristics. The service allows the development of a variety of learning scenarios, such as getting started with the colors, letters and numbers, shape recognition, recognition of objects from learning environment, learning foreign languages, and many others. Interaction between children and objects from learning environment should be simple and intuitive. To meet this goal for invisible computing, we simulate human-human interaction than use well known human-computer interaction models. We use a tangible user interface (TUI) based on following interaction techniques: touch, gesture recognition, natural voice-based output. Preliminary results show that the service can be used easily by young children, thanks to its tangible interface that is simple, easy to use, useful, accessible and invisible to technology. © 2013 ACM.