Year 2008 Volume 5(32) no. 1
INTERPRETED OBJECT ORIENTED HIGH LEVEL PETRI NETS (pp. 1-6)
Marius Brezovan, Eugen Ganea
Software Engineering Department, Faculty of Automation, Computers and Electronics,University of Craiova
Abstract: This paper proposes a new class of Petri nets called Interpreted Object Oriented High Level Petri Nets (IOOHLPN), and am algorithm for IOOHLPN semantics implementation. IOOHLPN are standard High Level Petri Nets augmented with an interaction component between a modeled system and its environment, and with some object orientation concepts. Both the formal syntax and dynamic semantics of the proposed formalism are defined. For semantics implementation of IOOHLPN, a token-player algorithm is proposed.
Keywords: Formal methods, Object oriented Petri nets, Interpreted Petri nets, Algebraic specifications.
A COMPLEX MATHEMATICAL EXPRESSION OPERATIONS TOOL(pp. 7-12)
Dorian Cojocaru 1 , Razvan Tudor Tanasie 1 , Dan Marghitu 2
1University of Craiova, Romania
2Auburn University, USA
Abstract: A tool for generating, deriving and numerically evaluating mathematical expressions was developed and implemented. This paper presents the structure that is the base of this tool, and a short example for an inverse kinematics application for tentacular robots is described. The designed structure and language permit easy adaptability for other applications, the presented example proving this aspect. The operational coordinates and then the Jacobean are stored and determined with the help of the generator and derivator functions of this tool. The algorithms used for creating and deriving the expressions are described. Finally, an interpreter was constructed to decrypt the expressions and then obtain their numerically values.
Keywords: expressions, generate, derive, evaluate, hyper-redundant robots, control.
EXPERIENCE IN CONFIGURATION, IMPLEMENTATION AND COMMISSIONING OF A
LARGE SCALE CONTROL SYSTEM
(BASED ON LHC CRYOGENIC DISTRIBUTION CONTROL SYSTEM) (pp. 13-17)
F Czeslaw Fluder1 , Juan Casas-Cubillos2 , Marek Ciechanowski3 , Wawrzyniec M.Gaj3 , Paulo Gomes2 ,
Pawel Jodlowski3 , Michal Klisch 3 , Tomasz Wolak 3 , Lukasz Zwalinski3
1 Department of Electrical Drive and Industrial Equipment, AGH University of Science and Technology, Krakow, Poland
2 Accelerator Technology Department CERN Geneva, Switzerland
3 Faculty of Physics and Applied Computers Science AGH University of Science and Technology Krakow, Poland
Abstract: This paper presents three years’ experience on configuration, implementation and commissioning of the Cryogenic Distribution Control System (CDCS) for the Large Hadron Collider. CDCS is based on 18 Programmable Logic Controllers, each serving up to 2 000 IOs, distributed in eight 3.3 km long sectors and two Accelerator Superconducting Cavities. Large scale and complexity of the control system forced development of several test procedures which allow validating each of the three standard hierarchical control system layers. The commissioning of the various sensors with infrastructure has been done by a Mobile Test Bench. Different types of actuators have been parameterized and their operationality has been checked in the field. Tests of remote IO modules and communication field buses have been performed using a portable PLC. For final check of all pneumatic actuators, an automatic test procedure has been implemented. Synoptic and tunnel coherence test has been performed to validate all control system layers.
Keywords: Control systems, Iinstrumentation, Commissioning, Cryogenics, LHC.
REASONING ON WIKIPEDIA(pp.18-23)
Adrian Giurca1, Emilian Pascalau 2, Gerd Wagner1
1 Brandenburg University of Technology, Germany
2Hasso Plattner Institute, Germany
Abstract: One role of Semantic Web technologies is to enable the Web content with a common sense meaning of information. This work aligns with the general effort to make available the Web content, particularly Wikipedia, for intelligent knowledge processing. The paper describes a solution to automatically extract semantic metadata from Wikipedia pages without any requirements to the existent content and to the users activities. The extracted metadata is source for semantic search along to the classical one. Large number of queries on Wikipedia will be much more sensibly answered. In addition, using semantic queries applications can generate all kind structured pages such as collections of data or statistics.
Keywords: Collaborative Encyclopedia, Reasoning, Semantic Web RDF, Category.
USING WAVELET TRANSFORM FOR SIGNATURE DETECTION OF A POLYNOMIAL FM
SIGNAL COVERED WITH A ZERO-MEAN GAUSSIAN NOISE (pp.24-29)
Cornelia Gordan1, Mircea Gordan1, Dorina Purcaru2, Romulus Reiz1, Nicolae Draghiciu1
1University of Oradea, Universitatii No.1, 410087 Oradea, Romania
2University of Craiova, Faculty of Automation, Computers and Electronics
The authors present some of their results obtained by using an original algorithm for the ridges (instantaneous frequency) estimation of polynomial frequency modulated FM signals. The method follows the following steps. First of all is obtained the wavelet time-frequency representation of the signal. Then this image is processed by Matlab program in order to extract the local maxim. At the end, is used also Matlab to interpolate the points for the maxim and to calculate the errors characterising the wavelet representation. The polynomial FM signals were covered with a zero-mean Gaussian noise.
Keywords: Wavelet, Time-frequency representation, Noise variance, Instantaneous frequency.
RECCOMENDATIONS FOR IMPLEMENTING LIFE-LONG-LEARNING (LLL) IN SMES (pp.30-35)
Institute for Work and Technology, FH Gelsenkirchen, Germany
Life-long-learning (LLL) is one of the most important aspect for dynamic companies and E-Learning can provide environments and tools for work task oriented and continuous learning. Results of projects show that such LLL strategies are missing in many European small and medium-sized companies. In this paper first factors which influence the successful adoption of LLL particularly of E-Learning are given. Secondly the paper presents a next step by including the results of the LLL readiness evaluation into the development of a LLL strategy. Thirdly the paper presents an example.
Keywords: Life-long-learning (LLL), E-Learning, Readiness, Small and medium-sized companies (SMEs).
WEAKNESSES AND IMPROVEMENTS OF A KEY DISTRIBUTION SECURITY PROTOCOL (pp.36-42)
Anca Jurcut1, Tom Coffey1, Reiner Dojen1, Robert Gyorodi2
1Department of Electronic & Computer Engineering,University of Limerick, Ireland
2Department of Computer Science,University of Oradea, Romania
Nowadays security protocols are a key component in providing security services for fixed and mobile networks. These protocols are designed to provide security services, such as key distribution, authentication and non-repudiation, over insecure networks. However, security protocols are vulnerable to a host of subtle attacks, such as replay, parallel session and type-flaw attacks. Designing protocols to be impervious to these attacks has been proven to be extremely challenging and error prone. This is evident from the large number of published protocols, which have later been found to contain various flaws - often several years after the original publication.
A new a new parallel session attack on Lowe’s modified version of the Wide-Mouthed Frog protocol is presented. This attack enables an intruder to masquerade as a legitimate user, thus defeating the authentication goal of the protocol. A fix for the protocol that prevents this new attack is proposed and discussed.
Security Protocols, Protocol Flaws, Protocol Attacks, Parallel Session Attacks.
XML GENERATOR FOR MULTIMEDIA PRESENTATION (pp.43-48)
Gheorghe Marian1, Nicolae Enescu1, Eugen Dumitrascu1, Marius Marian2
1Computer and Communication Engineering Department Faculty of Automation, Computers and Electronics
2Automatic Control DepartmentFaculty of Automation, Computers and Electronics
The main requirement is to realize a software application that allows the description of instructions and user manuals for varied categories of products through multimedia presentation. To realize the multimedia presentation for a product is necessary to know some programming languages that permit multimedia description (MACROMEDIA FLASH, JAVA, MICROSOFT VISUAL STUDIO, etc.). The application created in C# language, is a generator for description the functionality of a product only by using mouse, without programming knowledge’s. The application generates a XML file that contains the description of a product.
C#, .NET, GENMMX, editor, multimedia, XML.
IDENTIFICATION AND ADAPTIVE CONTROL OF CONTINUOUS TIME SYSTEMS
WITH DYNAMIC FRICTION(pp.49-58)
Constantin Marin, Virginia Finca, Radu Zglimbea
Department of Automation, University of Craiova
This paper extend the results obtained by the authors in Marin et al. (2007) regarding the self tuning control algorithm for mechanical systems with friction. Now dynamical models for friction forces are also considered. The adaptive control algorithm performs two actions: compensates the friction forces and adapts the parameters of a linear controller. It considers the so called generalized friction dynamic systems (GFDS) as defined in Marin et al. (2006), now with both the static friction models (SFM) and dynamic friction models (DFM) in self tuning process. For a simple feedback structure of the DFM the friction force is compensate by using state observers. The PID controller parameters are tuned by using distribution identification technique as developed in Marin et al. (2002). Some experimental results are presented to illuminate its advantages and practical use.
Identification, Adaptive control, Distribution theory, Friction systems.
DELAY EFFECTS ON STABILITY. AN OVERVIEW (pp.59-70)
Laboratoire des Signaux et Systemes (L2S, UMR CNRS 8506),
CNRS-Sup´elec, 3, rue Joliot Curie, 91190, Gif-sur-Yvette, France
In this paper, various methods for analyzing the stability of time-delay systems are outlined. The goal is to give an overview of the techniques encountered in the analysis of delay systems by interpreting the delay as an uncertainty of the system and reformulating the stability and/or control problem into a robust control framework.
Time-delay systems, Stability, Robust control.
A FRAMEWORK FOR TESTING ALGORITHMIC TRADING STRATEGIES(pp.71-79)
Daniel Paraschiv, Srinivas Raghavendra and Laurentiu Vasiliu
CIMRU/DERI National University of Ireland, Galway
Department of Economics National University of Ireland, Galway
Algorithmic trading and artificial stock markets have generated huge interest not only among brokers and traders in the financial markets but also across various disciplines in the academia. The emergence of algorithmic trading has created a new environment where the classic way of trading requires new approaches. In order to understand the impact of such a trading process on the functioning of the market, new tools, theories and approaches need to be created. Thus artificial stock markets have emerged as simulation environments to test, understand and model the impact of algorithmic trading, where humans and software agents may compete on the same market. The purpose of this paper is to create a framework to test and analyse various trading strategies in a dedicated artificial environment.
Artificial Stock Market, Double Auction, Back Testing, Algorithmic Trading, MACD.
ADVANCED CONTROL ALGORITHMS, FOR 3 PHASE INVERTERS CONTROL,
RUNNING ON NEC V850 MICROCONTROLLERS(pp.80-85)
Constantin Patrascu1 and Dan Popescu2
1 Computer Department, University of Craiova, ROMANIA
2 Control Department, University of Craiova, ROMANIA
The economic constraints and new standards legislated by governments place increasingly stringent requirements on electrical systems. The new generations of equipment must have higher performance parameters such as better efficiency and reduced electromagnetic interference. To fulfill these requirements the control units of the inverters must have powerful processors which can perform enhanced algorithms to reduce torque ripples and harmonics, and to improve dynamic behavior. In the first part, the authors make an overview of the main control methods of inverters in an AC motor control application and in an active power filter application. The second part provides an overview of NEC V850 capabilities for inverter control including some examples.
3 phase inverters, AC motors, Active power filters, NEC microcontrollers.
AN APPLICATION OF THE ALMOST LINEAR BEHAVIOR
(PILOT-IN-THE-LOOP-OSCILLATIONS) (pp. 86-92)
Vladimir Rasvan, Dan Popescu, Daniela Danciu
Department of Automatic Control, University of Craiova, Romania
The paper considers the PIO (Pilot-In-the-loop-Oscillations) problem for aircraft control in the context of the almost behavior for systems with sector restricted nonlinearities. This comes from the fact that the so called PIO II - corresponding to aircraft systems with active rate limiters - are related to the above mentioned ones. Consequently it appears that the validity of PIO I criteria (dealing with completely linear systems) might be extended to PIO II (with possible minor restrictions). The fact that the Popov absolute stability inequality is expressed in the frequency domain is an advantage for this unitary treatment. The paper considers the simplest Neal-Smith PIO I criterion which nevertheless leads to a critical case for time delay systems. The theoretical result is completed with simple simulations that are speaking for the correctness of this promising approach.
Aerospace, Human Machine Systems, Non Linear Control Systems, Robust Control.
TIRES PRODUCTION TRACKING USING RFID TAGS (pp. 92-97)
Stefan Udristoiu, Costin Badica, Dan Popescu, Sorin Nicola, Mircea Mihaiu
University of Craiova, Faculty of Automation, Computers and Electronics
The objective of the study was that, starting from a single tire, to determine an entire batch of tires which may show the same problems as the given tire in order to recall all of them. Tracking and tracing activities are defined as the capability to follow an element throughout several supply chain processes and players, and the ability to usefully exploit tracking data in order to redefine the history of an element.
Tracking Applications, Relational Databases, Database Structures, Intelligent Manufacturing Systems, Computer-aided Manufacturing, Verification.