Issue 1, Volume 1, 2007

A Lyapunov Shortest-Path Characterization for Markov Decision Processes
by Julio B. Clempner and Jesus Medel

Abstract: In this paper we introduce a modeling paradigm for developing decision process representation for shortest-path problems. Whereas, in previous work attention was restricted to tracking the net using Bellman?s equation as a utility function, this work uses a Lyapunov-like function. In this sense, we are changing the traditional cost function by a trajectory-tracking function which is also an optimal cost-to-target function for tracking the net. The main point of the Markov decision process is its ability to represent the system-dynamic and trajectory-dynamic properties of a decision process. Within the system-dynamic properties framework we prove new notions of equilibrium and stability. In the trajectory-dynamic properties framework, we optimize the value of the trajectory-function used for path planning via a Lyapunov-like function, obtaining as a result new characterizations for final decision points (optimum points) and stability. Moreover, we show that the system-dynamic and Lyapunov trajectory-dynamic properties of equilibrium, stability and final decision points (optimum points) meet under certain restrictions.
Automatic generation, HTML frames, HTML framesets, web application, web components
Full Paper, pp. 1-4


A New Paradigm for the Computational Complexity Analysis of Algorithms and Functions
by Ahmed Tarek

Abstract: There exists a variety of techniques for the computational complexity analysis of algorithms and functions. This analysis is foundational to the algorithmic and the functional performance. Asides from the big-oh complexity, there are other complexity notations, such as ?, ?, small o and small ! notational complexities. Complexity analysis is used to select an appropriate algorithm for solving a given problem using computer. Unfortunately, most of the prevailing approaches lack in simplicity, and consistency. Existing techniques are complex, and rather hard to realize in practice. There is a trend to exploit the notational complexities in the existing literature by treating those as functions instead of sets. In this paper, notational complexities and their applications paradigms are studied from the new perspectives. Simplified and consistent approaches are introduced that will make the analysis even simpler and easy to understand. Abused notational complexities are analyzed through the appropriate approach. Also, the paradigm introduced is extended to algorithms and functions involving multiple input variables.
Time Complexity, Space Complexity, Complexity Function, Notational Complexity, Complexity Paradigm, Algorithm Analysis.
Full Paper, pp. 5-12


Modern mathematical model using mixed p-z approach for the analyze of the switching power circuits
by Jiri Klima

Abstract: The mathematical method for the time-domain analysis of power converters with periodic pulse width modulation (PWM) is developed .The method is based on mixed p-z description of linear periodically time-varying system. The mathematical model uses the Laplace and modified Z transforms. The solution is not dependent on the number of the pulses of the PWM pattern. Instead of solution of algebraic equations the change of switching instants is reflected in the solution only by a change in two values mk and nk. All the results were visualized from the derived equations by the programme Mathcad. The derived equations are validated using a 3 kW three-phase inverter
Modified Z-transform, Laplace transform, switching circuits
Full Paper, pp. 13-20


Probability of collisions in Soft Input Decryption
by Nata?a ?ivi? and Christoph Ruland

Abstract: In this work, probability of collision in Soft Input Decryption has been analyzed and calculated. Collisions of cryptographic check values cause wrong verification results. Therefore, it is important to find an analytical form of a probability of collisions, which can be used for estimation of an efficiency of Soft Input Decryption. It is known, that shorter cryptographic check values cause often collisions. For that reason, the number of collisions for cryptographic check values has been tested and compared with the theoretical results.
Collisions, Probability of Collisions, Probability of a Match, Soft Input Decryption.
Full Paper, pp. 21-27


Just-in-Time Business Intelligence and Real-Time DecisioningDecryption
by Zeljko Panian

Abstract: Enterprise agility often may be the difference between organizational success and failure. The changing conditions in which businesses operate might be from customers, competitors, partners, market forces, regulatory forces, or world events. In these circumstances, decisioning is playing a critical role and must also be made in real time. Real-time decisioning is an analytic approach that allows organizations to automate the ?next best actions? based upon their goals and objectives. It embeds real-time analytic capabilities into business processes and substitutes traditional Business Intelligence (BI) which is oriented dominantly towards analyzing historical data coming from processes that are already accomplished.
Business agility, just-in-time business intelligence, decision-making process, real-time decisioning.
Full Paper, pp. 28-35


Continuation of Nonsmooth Bifurcations in Filippov Systems Using Singular Point Tracking
by Iv? Arango and John Alexander Taborda

Abstract: In this paper, we propose a novel numerical method for continuation of nonsmooth bifurcations in discontinuous piecewise smooth systems or Filippov systems which we are denominated Singular Point Tracking (SPT). We use the evaluation of the vector fields on the discontinuity boundary (DB) to analyze the dynamics of the systems without integration of the ODE sets or integrating only in the points computed by the SPT algorithm. We apply a classification of points and events on DB recently proposed. Local and global nonsmooth bifurcations are detected using the SPT method. Two principal advantages have the SPT method with other numerical methods to continuation of bifurcations in nonsmooth systems. First, the integration-free algorithms in the SPT avoid the well know numerical problems of these algorithms. Second, when the integration is unavoidable the SPT method computes the initial condition of the simulation to reduce the compute time. A piecewise smooth prey-predator model is used as illustrative example of the SPT method.
Bifurcation theory, continuation techniques, filippov systems, nonsmooth bifurcations.
Full Paper, pp. 36-49


Issue 3, Volume 1, 2007

A complete system of structural invariants for regularizable singular systems
by M. Isabel Garcia-Planas, A. Diaz

Abstract: Let (E; A;B;C) be a quadruple of matrices with E;A 2 Mn(C), B 2 Mn?m(C), C 2 Mp?n(C) representing a singular time-invariant linear system, Ex? = Ax + Bu, y = Cx. In this paper we present a collection of invariants for singular systems in terms of ranks of certain matrices, that permit us to reduce the system in a canonical form in such a way that the system is decomposed in following five independent subsystems: i) controllable and observable system, ii) controllable non observable system, iii) observable non controllable system, iv) Jordan system v) completely singular system.
Singular systems, proportional and derivative feedback, proportional and derivative output injection, canonical forms.
Full Paper, pp. 97-102


Numerical simulations used to detect the chaotic evolution of the exchange rate described by a nonlinear determinist system
by Mirela-Catrinel Voicu

Abstract: In this paper we present a study concerning the exchange rate evolution governed by a third-order nonlinear determinist discrete system. We present some results concerning the unique fixed point of the system, its stability and its attraction domain under certain values of parameters and we also present the existence of period-two cycles. Given the nonlinear nature of the system, its most complex type of behavior is the chaotic dynamics. We cannot detect this type of behavior using only analytical tools. For this reason, in order to detect the dynamics of the system, we will use numerical simulations. It is known that the Lyapunov exponents are a tool used to establish the type of behavior in nonlinear dynamics. We will calculate their values, in order to establish the type of dynamics. From our numerical simulations, we present a case in which the system displays a chaotic behavior. For this particular case we also consider a corresponding system of the second order. From the images of the figures in this paper we can observe a similarity between the images of attractors for each particular order of the systems.
nonlinear system, numerical simulations, chaos, attractors.
Full Paper, pp. 103-109


Adapting the teaching model to the new generation with the use of the ICT
by Javier Bilbao, Eugenio Bravo, Olatz Garc?, Concepci? Varela, Miguel Rodr?uez, Ver?ica Valdenebro, Gorka Garate, Izaskun Baro, Purificaci? Gonz?ez, and M. Emiliana Uranga

Abstract: In the last century the pedagogical and psychoeducational changes, advances and studies were the major figures in the educational programmes and in the way of teaching. In the century XXI, although these items continue with a great prominence, new tools have emerging which are very useful for teachers by means of Information and Communication Technologies (ICT). Moreover, in Europe an small revolution in the educational system is happening: the Bologna process. From our research group we are developing and using different tools to obtain and to facilitate this change of attitude: we have created some new and interactive material, similar to videos, we use the Moodle platform, we have created test for an auto-evaluation by students, etc. These new tools are implemented on the one hand in our subjects of the Engineering School of Bilbao and on the other hand in the subjects of the Spanish Group 9 of Universities by means of its Virtual Campus.
Computer applications, E-learning, ICT, Knowledge improvement, Teaching model.
Full Paper, pp. 110-114


The Design and Implementation of Database Encryption
by Noor Habibah Arshad, Saharbudin Naim Tahir Shah, Azlinah Mohamed, Abdul Manaf Mamat

Abstract: Information inside the database is shared by multiple parties such as internal users, partners, contractors and others. Sensitive data stored in database could be a target to attackers. The attacker for data stored in database not only from external but also from within the organization. Adding the database encryption, valuable information in database becomes more secure since the encrypted data ensure the confidentiality of the data. A new affine block cipher named Enhanced Affine Block Cipher technique is proposed for database encryption. This algorithm improves the weakness of the original affine cipher. The new encoding schema and modification Cipher Block Chaining (CBC) mode of operation for block cipher is designed for the new algorithm and then the prototype of the system is built and implemented into existing system for protecting user password. The result has shown that the algorithm is working properly, where the decryption process produced similar output as the original plaintext and it ran through specified configuration and evaluated thoroughly with respect to database approach and algorithm technique to prove the design.
Database, Enhanced Affine Block Cipher, Encryption, Decryption.
Full Paper, pp. 115-122


Maximizing Coverage in a Connected and K-Covered Wireless Sensor Network Using Genetic Algorithms
by Tahir Emre Kalayc?, Kas?m Sinan Y?ld?r?m, Aybars U?gur

Abstract: We are interested in an initial deployment strategy that maximizes the coverage area of wireless sensor network while preserving connectivity between nodes provided that all given hotspot regions are covered by at least k sensors. Sensing coverage of a sensor network characterizes how well an area is monitored or tracked by sensors. Connectivity is an important requirement that shows how nodes in a sensor network can effectively communicate. Some hotspot areas in the network are more important than other areas and need to be covered by more sensors. We propose a genetic algorithm based solution to find an optimal sensor node distribution. Experimental results are presented to evaluate our algorithm.
Wireless Sensor Networks, Genetic Algorithm, Coverage, Connectivity, k-Coverage,Optimization.
Full Paper, pp. 123-130




Issue 2, Volume 1, 2007

Growth of a Class of Plurisubharmonic Function in a Unit Polydisc I
by Amritasu Sinha

Abstract: The Growth of a non- constant analytic function of several complex variables is a very classical concept, but for a finite domain it is a recent concept initiated by Juneja and Kapoor[1],and later on substantiated by Sinha[2]. A Unit Polydisc is the most fundamental example of a Compact Riemann Surface, there is an upsurge in the area as being reflected in[4,5]. This is a very important concept and its applications can also be seen in Complex Analytical Dynamics. However in this present article we shall be concentrating on the growth parameter ?type? for such functions and also describe its Geometrical Properties.We have investigated upon some finer results on the growth of slowly varying functions. The above concept of Growth can also be utilized in Computer aided Tomography[7].
Analytic Function, Complex Analytical Dynamics,Growth Parameter, Type.
Full Paper, pp. 50-54


On the Ermanno-Bernoulli and Quasi-Ermanno-Bernoulli constants for linearizing dynamical systems
by F.I. Arunaye, H.White

Abstract: It is well known that the Ermanno-Bernoulli constants derived from the Laplace-Runge-Lenz vector of dynamical systems are efficiently used to reduce them to a system of harmonic oscillator(s) and conservation law in the context of point and nonlocal symmetries of dynamical systems. In this paper, we review Ermanno-Bernoulli constants and observe that one can also use analogous constants obtained from the Hamilton vector of dynamical systems to serve the same purpose. We report the generic natural variables for reducing such dynamical systems in two-dimensions and three-dimensions to a system of one harmonic oscillator and two harmonic oscillators respectively, and a conservation law with some examples. We also note that the symmetry groups obtained from the reduced systems using the alternative constants are realizations of those obtained from Ermanno-Bernoulli constants. We also report here that the symmetries of the original dynamical systems can be obtained from symmetries of the reduced systems.
Quasi, Constants, Symmetries, Vectors, Conservation, Oscillators, Laplace-Runge-Lenz, Hamilton, Coordinates, Dynamical.
Full Paper, pp. 55-60


A New Method for Enhanced Information Content in Product Model
by L?zl?Horv?h

Abstract: This paper introduces a new method in order to establish a better communication between engineers and modeling procedures during lifecycle management of product information in computer based engineering systems. The proposed method is intended as one of the initial attempts for resolution of an inherent conflict in product modeling. This conflict is between information content based thinking of engineer and information based processing in classical product modeling systems. The author applies a new sector of product model that describes information content for engineering activities. This sector controls engineering object data in the second sector for classical product model entities. In this manner, the new modeling can be interconnected with existing modeling in industrially applied engineering systems. Information content is stored in interconnected levels of the product model for human intent, meaning of concepts, engineering objectives, contexts, and decisions. This paper explains basic concepts, refers to research in the related topics, introduces role of humans and human-computer interactions in the proposed modeling, and details information content based product modeling. Following this, it emphasizes difficulties of decisions in case of high number of dependencies amongst engineering objects in large product models and proposes a new method for change management in those models. Implementation of the proposed product modeling methods can be realized in industrial professional modeling systems by using of their functionality for open architecture.
Product modeling, Lifecycle management of product information, Information content based product model, Design intent, Product changes, Affect zone of modified engineering object.
Full Paper, pp. 61-69


Elements of Security Aspects in Wireless Networks: Analysis and Integration
by Bojan M. Bakmaz, Miodrag R. Bakmaz, Zoran S. Bojkovic

Abstract: Security is a very critical part of wireless networks. This work presents a survey of some recent security aspects in wireless networks and discuss challenges in designing integrated security platform in wireless network environment. Firstly, recent security issues together with general security analysis, criteria and threats are emphasized. Starting from the point that security in wireless networks mainly involves authentication, confidentiality, integrity and authorization, integration of different wireless networks is analyzed. The importance of secure handover between heterogeneous networks is emphasized, too.
ntegrated security platform, handover, security treats, wireless networks.
Full Paper, pp. 70-75


Analyzing the set of uncontrollable second order generalized linear systems
by M. Isabel Garcia-Planas, J. Clotet

Abstract: In this paper we consider the space of second order generalized time-invariant linear systems, Ex? = A1x? + A2x + Bu, where E, A1, A2 2 Mn(C), B 2 Mn?m(C). We study the controllability of second order generalized systems by means the rank of a certain constant matrix that we will call ?the controllability matrix? of second order generalized linear systems. We use this matrix to study the geometry of the set of uncontrollable systems and we explicit the subset contained in the set of standardizable ones.
Second order linear systems, Feedback equivalence, Bundles.
Full Paper, pp. 76-83


Investigation of the Impact of Pilot Signals on the Performance of OFDMA Systems
by M. Haridim, M. Bank, V.Vulfin

Abstract: We introduce a new simulation method for OFDMA systems. The proposed method allows for the study of the impact of deterioration of subcarriers orthogonality, non-ideal synchronization and the phase noise of local oscillators. Using the proposed simulation method we have studied the impact of pilot signals on OFDMA performance. Results are compared to the performance of FBS systems which are a modified version of OFDMA systems using no pilot signals.
OFDMA, pilots, Doppler, FBS, simulation.
Full Paper, pp. 84-91


An Efficient Load Balancing Technology in CDN
by Yun Bai, Bo Jia, Jixiang Zhang, Qianggou Pu, Nikos Mastorakis

Abstract: The existing load balancing technology in CDN only emphasizes even load distribution among servers, and it doesn?t make full use of network topology information and file access history, so user request can?t get timely response. To solve the above problem, this paper puts forward a load balancing algorithm based on the Distributed binning strategy. This algorithm can make full use of network topology information and file access history as well as server load information, analyzing the popularity of files with the access history of the clusters of clients from the servers, efficiently finishing distribution and routing of the high popularity files among servers so that users can closely obtain the required contents, ease Internet congestion and enhance response speed of user accessing websites.
CDN, distributed binning strategy; history record, load balancing, network topology
Full Paper, pp. 92-96


Issue 4, Volume 1, 2007

Motion Controller Design for the Speed Control of DC Servo Motor
by Mehmet Akari and ?smail Temiz

Abstract: This paper presents a study on speed control problem for Direct Current (DC) servo motor. In this study DC servo motor?s mathematical model and equations were extracted and there were three different motion controller designed for controlling the angular velocity. It was created simulation model at the Matlab programme and implemented proportional-integral, fuzzy and adaptive neuro fuzzy inference system controllers respectively while it was working variable conditions. At the servo motor application it is expected that no overshoot, settling reference value quickly and minimum influence on the system stability.
DC Servo Motor, Proportional- Integral, Fuzzy, Adaptive Neuro Fuzzy Inference System
Full Paper, pp. 131-137


Integration method and Runge-Kutta method
by Wannaporn Sanprasert and Ungsana Chundang

Abstract: In [1], M. Podisuk, U. Chundang and W. Sanprasert introduced the integration method for finding the numerical solution of the initial value problem of ordinary differential equation which turned out to be the multi-step method. In this paper, the single step method of this integration method with the help of Gauss-Legendre Quadrature integration formula and the Taylor series expansion is explored. The results of some examples that include the initial value problem of fourth order of ordinary differential equation are shown. These results are compared to the results that obtain by the Runge-Kutta method.
Gauss-Quadrature-formula Gauss-Legendre-Quadrature-formula Integration-method Initial-valueproblem Taylor series expansion Runge-Kutta-method
Full Paper, pp. 138-143

Smoothing curve by orthogonal polynomials
by Sukpak Pansomboon and Pongpan Rattanathanawan

Abstract: The interpolation by polynomial of degree n, p (x) n , may smooth any curve y = f (x) with the condition that this polynomial must passes through n +1 points of the curve y = f (x) . This condition may make the shape of the curve of y p (x) n = different from the exact shape of curve of y = f (x) especially in the case that the points of f (x) are obtained from an experiment which may not be the exact point of the curve y = f (x) . But the least square approximation by orthogonal polynomial, q (x) n , may give the better shape than the interpolation by polynomial, p (x) n . However the curve of y q (x) n = may not pass through any exact point of the curve y = f (x) . M.Podisuk, P.Rattanathanawan and P.Phataranavik in [1] introduced the sequences of orthogonal polynomials with step functions as their weight functions but they did not use them for least square approximation. In this paper, the sequences of orthogonal polynomials with step functions as their weight functions will be used for least square approximation.
Full Paper, pp. 144-150

Machine learning approach to authorship attribution of literary texts
by Urszula Sta?czyk, Krzysztof A.Cyran

Abstract: Machine learning approaches are employed in the variety of feature extraction and classification tasks because of their efficiency in dealing with huge amount of data. The paper addresses the application of Artificial Neural Networks as the processing engine for textual analysis of literature oriented at authorship attribution, which falls within the scope of data mining techniques. Author identification is a problem of significant importance not only from academic or historic point of view as in cases of disputed authorship of some literary works but in more current and sinister affairs of forensic nature as well. To solve the problem various methodologies have been employed or invented, belonging either to statistic-dedicated computations or machine learning algorithms, the example of the latter category presented in the paper.
Machine learning, stylometry, artificial neural networks, author identification
Full Paper, pp. 151-158

On employing elements of Rough Set Theory to stylometric analysis of literary texts
by Urszula Stanczyk, Krzysztof A. Cyran

Abstract: Rough Set Theory deals with imperfect knowledge about the Universe and objects that comprise it, and such knowledge can be interpreted and manipulated in many ways. The paper describes application of rough set-based approach to the problem of stylometric analysis of texts that by the notion of writer invariant enables to identify authors of disputed or unattributed works. Writer invariant is the primary stylometric concept which corresponds to such unique characteristic that expresses the writing style of a person, allowing for distinguishing texts authored by this person from all others. It can be obtained in a myriad of techniques usually belonging with either statistical analysis or machine learning methodologies, with RST addressed in this paper being the example of the latter category.
Stylometry, rough sets, authorship attribution, relative reduct, decision algorithm.
Full Paper, pp. 159-166