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ANNALS OF THE UNIVERSITY OF CRAIOVA

Series: AUTOMATION, COMPUTERS, ELECTRONICS and MECHATRONICS


    ISSN: 1841-0626 CNCSIS code 11 category B+ internationally indexed, starting with 2010, (Copernicus, Inspec)
    Semiannual publication
    Occasionally, conferences dedicated special issues may be published

    Year 2014 Volume 11(38) no. 2
  1. Mathematical Model of Heat Flows from Shelters for Telecommunications Equipments (pp. 1-6)

    Gheorghe Doru DICU
    Doctoral School of the Faculty of Automation, Computers and Electronics, Craiova, Romania dicu_doru@yahoo.com


    Abstract: This paper develops a solution for keeping the ventilation of some isolated rooms (shelters) designed for telecommunications equipment, monitored by a controller which administrates the heating, the cooling and the air exchange with the outside of the room through ventilation. This thing leads to a significant increase of the electricity consumption, to an increase of administration costs which, at present, are very high, but also to an increase of the operational reliability of telecommunications equipments.
    Keywords: Parameters, Ambient temperature, Monitoring, Ventilation, Equipment, Telecommunications.

  2. An Overview of the Hiper-Redundant Robot HIPROB-I (pp. 7-12)

    Sorin DUMITRU, Florin MANTA, Cristina RESCEANU
    Faculty of Automation, Computers and Electronics, University of Craiova
    e-mail: dumitru@robotics.ucv.ro, manta@robotics.ucv.ro, cristina@robotics.ucv.ro


    Abstract: In these days can be observed a grown in interest regarding the robots with high mobility degree, wanted for their capability to avoid obstacles and reach difficult positions in their working space. One particular class of these robots consists in tentacle robots, biologically inspired by cephalopods. This paper present the steps followed for building a hyper-redundant robotic structure called HIPROB-I. It is shown how the CAD model was made, the preparation and built of the physical robotic structure and the finite-element analysis.
    Keywords: hyper-redundant, CAD, finite-element, actuation, flexible.

  3. Lossless Compression in Image Processing Technologies and Applications (pp. 13-18)

    Bogdan POPA, Dan POPESCU
    Department of Automation and Applied Informatics, University of Craiova, Craiova, Romania
    e-mail: bogpo89@yahoo.com, dpopescu@automation.ucv.ro


    Abstract: This research work provides lossless data compression methodologies, an extensive research study of methods of compression and image processing algorithms starting from the actual materials and functions made by several processing technologies today, resulting in finding solutions and innovative ways to improve the actual studies. Data compression is a process that reduces the data size, removing the excessive and redundant information. Today there are a lot of different data compression methodologies, which are used to compress different data formats like, video, audio, image files. This study represents a comparison of several compression methods based on previous research and the analysis in the context of their current needs.
    Keywords: Data compression, image processing, lossless compression, wavelet transform.

  4. System for data aquisition with real-time complex processing of a bearing vibration (pp. 19-24)

    Ion Marian POPESCU
    Department of Automation, Energy and Environment, University Constantin Brâncusi, Targu Jiu, Romania (e-mail: po_marian@yahoo.com)
    Postdoctoral Researcher at University of Craiova, Craiova, Romania (e-mail: pmarian@automation.ucv.ro)


    Abstract: The current technical possibilities, based at hardware level, on the development of a high power computing for microprocessor systems, to which are added consistent software tools have led to increasing complexity of information processing in two aspects that are in opposition: working in real-time and complexity of processing. The current performance in the processing of real-time information, and automatic control are possible due to a very dedicated connections between hardware and software. The idea of using FPGA technology in conjunction with microprocessors and higher-level software, allows the design of information processing applications in real time with high complexity.
    Keywords: real-time processing, FPGA, bearing vibration.

  5. Traction Asynchronous Motor Fed by Power Converter Controlled by Direct Torque Control Method (pp. 25-30)

    Razvan PREJBEANU
    RELOC S.A., 109, Bd. DECEBAL, 200746, CRAIOVA, ROMANIA (e-mail: razvan.prejbeanu@relocsa.ro).


    Abstract: In the case of asynchronous motor with squirrel cage, rotor currents cannot be measured, and the implementation of vector control (field - oriented control of stator, rotor or magnetization fluxes) requires information about the module and the phase (position) of the stator, rotor respectively magnetization phasors fluxes. The control is performed in the reference systems joined with the stator, rotor or magnetization fluxes, resulting the stator currents components. Direct torque control (DTC) method describes how the torque and the speed are directly adjusted by the electromagnetic status of the motor, similar to a direct current (DC) motor, unlike the traditional pulse width modulation (PWM) mode which uses the motor control by adjusting frequency and voltage from the output of the converter. DTC is the first technology that enables control by means "real" motor torque and flux control variables.
    Keywords: converter, asynchronous motor, control, torque, regulator.

  6. Image Processing Using Frequency Separation Technique (pp. 31-35)

    Virginia Maria RADULESCU
    Department of Automatic Control, University of Craiova, Craiova, Romania (e-mail: virginia@automation.ucv.ro)


    Abstract: The evolution of creation and use of high-quality images of the last few years requires an updated and continuously study in the field of image processing. In the following are discussed issues related to the treatment and improvement of the quality of the images. It is proposed a technique that treats images in terms of technical issue, which is based on its frequency in the decomposition. The study will also present examples of implementation of these methods and their results.
    Keywords: image, processing, analysis, model, frequency methods.

  7. Improved Smith Predictor Structures Applied in Electric Plant Control (pp. 36-41)

    Ionut Cristian RESCEANU, Cristina Floriana RESCEANU
    University of Craiova , Faculty of Automation, Computers and Electronics (e-mail: {resceanu, cristina} @robotics.ucv.ro)


    Abstract: This paper presents studies regarding remote control of some electric rotating machines - the DC motor and the synchronous generator, using the improved dynamic Smith predictor and double Smith predictor structures. The synchronous generator and the DC motor are studied based on transfer functions (model). One of the most important aspects when applying such control strategies is the study of network delays which is largely depicted here in a large number of simulations. The paper also contains an amply detailed case study performed on a Quanser SRV-02 servo motor controlled via Matlab® and Wincon®. For comparison, we use a non-predictor structure in order to underline the improvements brought on by using the presented Smith predictor configurations.
    Keywords: networked control system (NCS), Smith predictor, networked induced delay.

  8. Nonlinear dynamics in biotechnological processes: Analysis and case studies (pp. 42-47)

    Monica ROMAN
    Department of Automation and Electronics, University of Craiova, A.I. Cuza 13, RO-200585, Craiova, Romania (e-mail: monica@automation.ucv.ro).


    Abstract: This paper presents the dynamics analysis of some biochemical processes under different reaction kinetics, highlighting the influence of physical chemical factors over the evolution of the process run. The models of reaction kinetics are integrated in the general pseudo bond graph models of the biochemical processes as bond graph elements, underlining and using the modularity advantage of bond graph modeling methodology. First, a prototype bioprocess is used in order to analyze the behavior of some process parameters under the influence of substrate and biomass concentrations on the specific growth rate. Second, some of these reaction kinetics are considered for the analysis of a more complex bioprocess of lipase production. The simulations are performed in 20sim modeling and simulation environment.
    Keywords: nonlinear systems, modeling, biotechnology, bond graphs.