bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple-valued regenerative CMOS logic circuits with high-impedance output state
Authors: Bundalo Dusanka , Djordjevic Branimir , Bundalo Zlatko
Published: October 2011

Principles and possibilities of synthesis and design of multiple-valued (MV) regenerative CMOS logic circuits with high-impedance output state and any logic basis are proposed and described in the paper. Two principles of synthesis and implementation of CMOS regenerative multiple-valued logic circuits with high-impedance output state are proposed and described: the simple circuits and the buffer/driver circuits. The schemes of such circuits are given and analyzed by computer simulations. Some of computer simulation results confirming descriptions and conclusions are also given in the paper.
Ground fault distribution on overhead transmission lines
Authors: Vintan Maria , Buta Adrian
Published: October 2011

When a ground fault occurs on an overhead transmission line in a power network with grounded neutral, the fault current returns to the grounded neutral through the tower structures, ground return paths and ground wires. This paper presents an analytical method in order to evaluate the ground fault current distribution in an effectively grounded power network. The effect of soil resistivity, ground resistance of towers and power line configuration, on the magnitude of return currents, has been examined.
Induction motors with YY/D connection change for efficiency and power factor increasing at partial loads
Authors: Kostic Miloje , Radakovic Jovan
Published: October 2011

It is established that there exists a significant possibility for energy savings, on the basis of application of induction motors with YY/D connection change proposed in this paper, especially for power to 30 kW. In connection D (0.866Un), total losses and reactive loads are reduced to loads up to 75-85%. Benefits of such motors would be significant because more than 80% induction motors are light loaded (mean value ? 70%). In such manner one motor with two characteristics is attained, but that is better than to offer to the market two different motors, because only in exploitation it is possible to accurately select the one which is working with greater efficiency values in given conditions. However, at the motor with YY/D winding it is always possible, by selection of corresponding connection for (mean value) load measured in operation. Even, with connection change it is possible to adjust to load changes in future. Moreover, at loads ? 30%, energy saving by induction motors with YY/D connection is greater than the one using induction motors with thyristor controllers. Induction motors YY/D connection application may be economical in cases where it is not recommended to use higher costs of energy efficiency of motors.
Al-Alaoui operator and the α-approximation for discretization analog systems
Authors: Al Adnan-Alaoui
Published: October 2011

The a-approximation for discretization of analog systems was recently introduced. In this paper it is shown that the a-approximation is exactly the same as the parameterized Al-Alaoui operator.
Characteristics of inductive loops applied in thelematics
Authors: Miric Bratislav , Vuckovic Darko , Spalevic Petar
Published: October 2011

The intention of this paper is to give a bright review of a process triggering equipment that is connected to the inductive loop when a vehicle is moving above it. First, we tried to approximate the bottom of the vehicle with rectangular loop. On that base we developed a simulation model of a vehicle moving above the loop. Then we measured the triggering point on the real condition. The intention of these measurements was to find how the triggering point depends on position of the vehicle (vehicle offset) above the loop and how it depends on the vehicle velocity. On the basis of the obtained results that are shown in this paper, it becomes more clear when the triggering of the equipment that is connected to the inductive loop occurs when a vehicle is moving above the loop.
Use of non-linear programming in designing the self-starting permanent magnet synchronous micromotors
Authors: Stanev Iliya
Published: October 2011

In this paper the possibility of a flexible use of non-linear mathematical programming is shown both for the optimal design of a self-starting permanent magnet synchronous micromotor and for resolving the problem of identification of its parameters without any essential changes of the program.
Voltage sag drop in speed minimization in modern adjustable speed drives
Authors: Petronijevic Milutin , Jeftenic Borislav , Mitrovic Nebojsa , Kostic Vojkan
Published: October 2011

This paper researches behavior of rotor field oriented (RFO) and direct torque controlled (DTC) drives in speed controlled application in voltage sags circumstances. Problems in application will be able to appear especially in work cases with speed and torque close to rated, even in a case when typical voltage tolerance curves show no drive trips. To overcome appeared drop in speed it was posed a field weakening algorithm during voltage sag. Analytic calculation and numerical simulation were presented in detail in this work. Knowing delay in RFO flux response and prompt DTC flux recall, methods for dynamic performance improving were advised.
Competitive learning algorithms for data clustering
Authors: Budura Georgeta , Botoca Corina , Miclău Nicolae
Published: October 2011

This paper presents and discusses some competitive learning algorithms for data clustering. A new competitive learning algorithm, named the dynamically penalized rival competitive learning algorithm (DPRCL), is introduced and studied. It is a variant of the rival penalized competitive algorithm [1] and it performs appropriate clustering without knowing the clusters number, by automatically driving the extra seed points far away from the input data set. It does not have the 'dead units' problem. Simulations results, performed in different conditions, are presented showing that the performance of the new DPRCL algorithm is better comparative with other competitive algorithms.
Enhancing robustness of speech recognizers by bimodal features
Authors: Gavat Inge , Costache Gabriel , Iancu Claudia
Published: October 2011

In this paper a robust speech recognizer is presented based on features obtained from the speech signal and also from the image of the speaker. The features were combined by simple concatenation, resulting composed feature vectors to train the models corresponding to each class. For recognition, the classification process relies on a very effective algorithm, namely the multiclass SVM. Under additive noise conditions the bimodal system based on combined features acts better than the unimodal system, based only on the speech features, the added information obtained from the image playing an important role in robustness improvement.
Neural network for optimization of routing in communication networks
Authors: Kojic Nenad , Reljin Irini , Reljin Branimir
Published: October 2011

The efficient neural network algorithm for optimization of routing in communication networks is suggested. As it was known from literature different optimization and ill-defined problems may be resolved using appropriately designed neural networks, due to their high computational speed and the possibility of working with uncertain data. Under some assumptions the routing in packet-switched communication networks may be considered as optimization problem, more precisely, as a shortest-path problem. The Hopfield-type neural network is a very efficient tool for solving such problems. The suggested routing algorithm is designed to find the optimal path, meaning, the shortest path (if possible), but taking into account the traffic conditions: the incoming traffic flow, routers occupancy, and link capacities, avoiding the packet loss due to the input buffer overflow. The applicability of the proposed model is demonstrated through computer simulations in different traffic conditions and for different full-connected networks with both symmetrical and non-symmetrical links.
Kanalkapazität vielpaariger symmetrischer Kupferkabel, Teil II: Ausnutzung der Fernnebensprechwege
Authors: Lange Christoph , Ahrens Andreas
Published: October 2011

(nemacki) In den vielpaarigen symmetrischen Kupferkabeln der Ortsnetze begrenzt das Nebensprechen wesentlich die erreichbare ? bertragungskapazit?t. In einem zugeh ?rigen ersten Teil dieses Beitrages wurde die Kapazit?t von symmetrischen Leiterpaaren innerhalb vielpaariger Kabel bei St?rung durch Nah- und Fernnebensprechen in bidirektional betriebenen Kabeln sowie bei alleiniger Fernnebensprechst?rung in unidirektional genutzten Kabeln berechnet. In diesem zweiten Teil des Beitrages wird f?r unidirektional betriebene Kabel der Blickwinkel ver?ndert und die Kanalkapazit?t daf?r berechnet, dass die ?ber die Fernnebensprechpfade auf benachbarte Aderpaare ?bergekoppelten Signalanteile ebenso wie das direkt ?bertragene Signal als Nutzsignal betrachtet werden. Als Ergebnis zeigt sich, dass die Kanalkapazit?t von Kabelb ?ndeln durch die Ausnutzung des Fernnebensprechens gegen?ber der Kapazit?t von (fiktiven) B?ndeln mit perfekt geschirmten Einzelpaaren gesteigert werden kann. Noch weitaus deutlicher wird der erzielbare Kapazit?tsgewinn gegen?ber der praktisch relevanten Kapazit?t von Kabelb?ndeln mit nicht geschirmten Aderpaaren bei gegenseitiger Fernnebensprechst?rung. Mit zunehmender Anzahl in einem B?ndel zusammengefasster Aderpaare werden die erzielbaren Kapazit ?tsgewinne gr??er, wobei insbesondere bei kurzen Kabeln die Steigerung der Kanalkapazit?t durch Ausnutzung des Fernnebensprechens besonders deutlich ist.
Low frequency TM plane-wave scattering from a two-layer double-strip grating with equal gaps
Authors: Filipovic Dragan , Dlabac Tatijana
Published: October 2011

This paper treats the low-frequency TM plane-wave scattering from a two layer double-strip grating with equal gaps. The problems solved by using a simplified network model which takes into account only the basic (n=0) mode. Numerical results are given for the magnitude of the basic mode reflection coefficient versus the relative grating period.
Modeling of the criteria for measurement and assessing the quality of university education
Authors: Hristova Maria , Zhelezarov Iliya
Published: October 2011

The paper deals with the application of expert methods and correlation analysis during multi-criteria measurement and assessment of the quality of university education. The paper is founded on the precondition that the quality of university education has to be measured and the quantitative assessments have to be obtained by scalarization of preliminarily defined criteria, which depend on the single indices about quality of training. The multi-componential criteria functions of indices, the correlation dependences between them, the coefficients of weight have been studied applying the method of expert assessment.
Closed-form variance formula of the RPHD single-tone frequency estimator
Authors: Toma Liviu , Sabata De , Mischie Septimiu
Published: October 2011

In this paper, we provide a very convenient, closed-form formula for the variance of the single tone frequency estimator in the reformed Pisarenko harmonic decomposer method. Several computer experiments show that calculated and measured variances are in excellent agreement. Our formula is useful when a small number of signal samples are used for frequency estimation, as asymptotic forms can lead to important errors.
Reduction of operational amplifiers finite gain effects in switched-capacitor low-pass notch biquads
Authors: Radev Nikolay , Ivanov Kantcho
Published: October 2011

An combined approach for reducing the errors in the notch frequency fz, in the pole frequency fp, in the quality factor Qp and in the amplitude Hp at the pole frequency of switched-capacitor low-pass notch biquads is presented. At first, the conventional integrators in the biquads are replaced with gain and offset-compensated integrators. Subsequently, the errors Dfz/ fz, Dfp fp, DQp/Qp and DHp/Hp are minimized by modifying the values of the integrating capacitances and of the appropriately chosen zero-forming and pole-forming capacitances. The effectiveness of this approach is demonstrated by designing two low-pass notch biquad topologies which realize the same transfer function.
On strong consistency of a class of recursive stochastic Newton-Raphson type algorithms with application to robust linear dynamic system identification
Authors: Kovacevic Ivana , Kovacevic Branko , Djurovic Zeljko
Published: October 2011

The recursive stochastic algorithms for estimating the parameters of linear discrete-time dynamic systems in the presence of disturbance uncertainty has been considered in the paper. Problems related to the construction of min-max optimal recursive algorithms are demonstrated. In addition, the robustness of the proposed algorithms has been addressed. Since the min-max optimal solution cannot be achieved in practice, an approximate optimal solution based on a recursive stochastic Newton-Raphson type procedure is suggested. The convergence of the proposed practically applicable robustified recursive algorithm is established theoretically using the martingale theory. Both theoretical and experimental analysis related to the practical robustness of the proposed algorithm are also included. .
An experimental laboratory system for monitoring and detection of electrical drives systems with induction machines
Authors: Mihet-Popa Lucian , Prostean Octavian , Szeidert Iosif
Published: October 2011

This paper focuses on developing and testing a comprehensive monitoring and detection laboratory system, for use in electrical drives systems using Induction Machines. The article aims to provide further documentation for an advanced condition monitoring system including transducers, signal conditioning box and data acquisition device, in order to avoid undesirable operating conditions and to detect and diagnose incipient electrical faults. Also, this paper suggests the possibility of diagnosing different types of failures by means of spectral analysis of current and voltage. .
Modeling and optimization of electric furnace transformer unit
Authors: Stoykov Kiril , Ivanov Petar , Brandisky Kostadin
Published: October 2011

In this paper the modelling and optimization of a single-phase electric furnace transformer unit is considered. First, the distribution of the magnetic fluxes is analysed, using 3D finite element analysis. Then, some possibilities for optimization of the core dimensions to diminish the maximum flux density and the power losses are shown. .
Sliding mode control technique for an induction motor drive supplied by a three-level voltage source inverter
Authors: Ryvkin Sergey , Schmidt-Obermöller Richard , Steimel Andreas
Published: October 2011

The possibility of using sliding-mode (SM) technique for an induction motor drive with a class of inverters dedicated to high power, the three-level voltage-source inverter (3LVSI), has been presented. A designed control based on the proposed two-step design procedure is discussed; drive simulation results are shown. .
Comparison of higher order fem and MOM/SIE approaches in analyses of closed- and open-region electromagnetic problems
Authors: Ilic Milan , Ilic Andjelija , Notaros Branislav
Published: October 2011

We investigate the efficiency of the two most popular frequency-domain approaches in computational electromagnetics (CEM); the finite element method (FEM) and the method of moments based on the surface integral equation (MoM/SIE), both in the context of the higher order modeling. We compare the performances of the two approaches in two simple three-dimensional (3-D) problems with similar meshes, chosen as benchmark examples. The chosen examples demonstrate full-wave analysis of a wave-guiding structure (a closed-region problem) and a scatterer in free space (an open-region problem). .
An efficient generator voltages control method for improvement of voltage-reactive states in transmission network
Authors: Popovic Dragan , Stojkovic Milos
Published: October 2011

This paper presents an efficient generator voltage control method for improvement of voltage-reactive states in transmission networks. This method enables fast and sufficiently accurate definition of generator voltages to realize the favorable voltage-reactive states. In peak load state, this generator voltage control is made to improve the economic operation, e.g. to reduce the active and reactive power losses or to enlarge the reactive reserve of generators. In minimum load state, this voltage control is made to reduce the generator under-excitation states, or to make the favorable redistribution of those under-excitation states. The verification of method proposed is made in context of steady-state and dynamic simulation models, on the examples of realized and perspective states of Serbian transmission network, in own wide environment. .
Lebesgue points of multi-dimensional functions
Authors: Weisz Ferenc
Published: October 2011

Lebesgue and Walsh-Lebesgue points are introduced for higher dimensional functions and it is proved that a.e. point is a (Walsh)-Lebesgue point of a function f from the space L(log L)d-1. Every function f ? L(log L)d-1 is Fej?r summable at each (Walsh)-Lebesgue point. .
Quasi-measures and Walsh series
Authors: Plotnikov Mikhail
Published: October 2011

Properties of quasi-measures on the dyadic group G and on the product group Gd are considered and applications of this properties to the theory of the uniqueness of Walsh series are discussed. .
Almost everywhere convergence of a subsequence of the logarithmic means of Vilenkin-Fourier series
Authors: Gát György , Nagy Károly
Published: October 2011

The main aim of this paper is to prove that the maximal operator of a subsequence of the (one-dimensional) logarithmic means of Vilenkin-Fourier series is of weak type (1, 1). Moreover, we prove that the maximal operator of the logarithmic means of quadratical partial sums of double Vilenkin-Fourier series is of weak type (1, 1), provided that the supremum in the maximal operator is taken over special indices. The set of Vilenkin polynomials is dense in L1, so by the well-known density argument the logarithmic means t2n(f) converge a.e. to f for all integrable function f. .
Closed-system quantum logic network implementation of the Viterbi algorithm
Authors: Al-Rabadi Anas
Published: October 2011

New convolution-based multiple-stream error-control coding and decoding schemes are introduced. The new coding method applies the reversibility property in the convolution-based encoder for multiple-stream error-control encoding and implements the reversibility property in the new reversible Viterbi decoding algorithm for multiple-stream error-correction decoding. The complete design of quantum circuits for the quantum realization of the new quantum Viterbi cell in the quantum domain is also introduced. In quantum mechanics, a closed system is an isolated system that can't exchange energy or matter with its surroundings and doesn't interact with other quantum systems. In contrast to open quantum systems, closed quantum systems obey the unitary evolution and thus they are reversible. Reversibility property in error-control coding can be important for the following main reasons: (1) reversibility is a basic requirement for low-power circuit design in future technologies such as in quantum computing (QC), (2) reversibility leads to super-speedy encoding/decoding operations because of the superposition and entanglement properties that emerge in the quantum computing systems that are naturally reversible and therefore very high performance is obtained, and (3) it is shown in this paper that the reversibility relationship between multiple-streams of data can be used for further correction of errors that are uncorrectable using the implemented decoding algorithm such as in the case of triple-errors that are uncorrectable using the classical irreversible Viterbi algorithm. .
The analysis of a rural distribution network with distributed generation in catchment area of Stara Planina
Authors: Radosavljevic Jordan , Jevtic Miroljub , Klimenta Dardan
Published: October 2011

The rural distribution network with 11 micro hydropower plants (MHPs) of 10 kWto 50 kW, in catchment area of Stara Planina, is analyzed in the paper. The network is characterized by: higher generation than consumption, outstanding variation of generated energy during a year, permanent increase of number of constructed and connected MHPs and significant space dispersion of MHPs. In such network the voltage deviations were appeared out of standard limits. After operation of MHPs during three years, their cost efficiency is analyzed and procedure of voltage regulation in the network is developed in the paper. The procedure includes calculation and setting of optimal off-voltage tap changer positions at transformers, twice in year, i.e. in season with higher generation and in season with lower generation. At outlying nodes (near outlying MHPs), where voltage was not regulated within standard limits (using this procedure), voltage regulation is performed by two autotransformers of 0.95/0.4 kV that are posted on posts of outlying nodes supply line. This procedure is proposed as a model which can be applied in future similar rural networks with MHPs that will be constructed in West Balkan countries after acceptance of EU directives about renewable energy sources. .
Temperature independent current conveyor precision full-wave rectifier for low-level signal
Authors: Djukic Slobodan
Published: October 2011

A circuit that provides precision rectification low-level input signal with low temperature sensitivity is presented in this paper. It utilizes an improved second type current conveyor based around current-steering output stage and voltage biased silicon diodes, rather than more usual current mirrors. Proposed design of the precision rectifier ensures good current transfer linearity in the range that satisfy class A of the amplifier and good voltage transfer characteristic for low level signals. Distortion during the zero crossing of the input signal is practically eliminated. Design of the proposed rectifier is realized with usual components that can be bought in the market. .
Digital FIR filter architecture based on the residue number system
Authors: Stamenkovic Negovan
Published: October 2011

In this paper, architecture of residue number system used in FIR filters, is presented. For many years residue number coding has been recognized as a system which provides capability for implementation of a high speed addition and multiplication. These advantages of residue number system coding for the high speed FIR filters design results from the fact that an digital FIR filter requires only addition and multiplication. The proposed FIR filter architecture is performed as series of modulo multiplication and accumulation across each modulo. A numerical example illustrates the principles of FIR filtering of an 32 order low pass filter. This architecture is compared with FIR filters direct synthesis. .
Efficiency of the 3-phase system to provide energy under low frequency induction heating of CWRs
Authors: Miedzinski Bogdan , Habrych Marcin , Okraszewski Zenon , Wang Xin , Xu Lj
Published: October 2011

In this paper the efficiency of heating of continuous welded rails (CWRs) under track laying when 3-phase low frequency supplying system is applied has been carefully considered. On the basis of computations confirmed by the investigated results, for different heaters location as well as different voltage phase shifts, the conclusions concerning proper selection of the structure of the energy supplying systems are formulated. .
An external body in protected area
Authors: Cvetkovic Zlata , Petkovic Bojana , Peric Mirjana
Published: October 2011

In practice, often there is a need for modeling systems for canceling the Earth electrostatic field. For this purpose, a linear circular loop can be used. The realized protection is as better as the used ring is thicker. In practical applications, a system of coaxial linear loops is used instead of one thick ring. In order to find the influence of protected object shape and volume to the electrostatic protection efficiency, a protected object is modeled as a half spherical electrode, placed with its flat side on the ground. According to the theoretical analysis, a general numerical program has been developed and numerical results are shown graphically. .
Determination of rotor slot number of an induction motor using an external search coil
Authors: Keysan Ozan , Ertan Bülent
Published: October 2011

This paper describes determination of the number rotor slots of an induction motor from the induced emf in an external search coil. This information is needed in prediction of motor speed from the external search coil induced voltage. The approach is based on identifying saliency harmonics and rotor slot harmonics, via FFT analysis of the external search coil emf. The proposed approach is tested on an induction motor driven by the mains supply. The experiments are repeated with a PWM supply. It is shown that the method works well in both cases and the number of rotor slots of the test machine is accurately predicted. .
Analysis of DC converters for wind generators
Authors: Lazarov Vladimir , Roye Daniel , Zarkov Zahari , Spirov Dimitar
Published: October 2011

The present paper investigates the system behavior of a rectifier and a DC boost converter used in a wind generator with variable speed. In many cases a combination of diode rectifier and a DC boost converter is used as interface between the generator and the inverter in order to match the requirements for the DC bus voltage. Different models of the converters have been developed in Malab/Simulink and PSPICE environments. Comparison between the simulations and experiments is shown. The power losses are also discussed. .
Structuring of business rules in information system design and architecture
Authors: Novakovic Igor , Deletic Velimir
Published: October 2011

The approach to business rules introduces a new layer of business rules to the Information System design and architecture. As the rules are separated from the data and presentation aspects of the system, numerous changes have to be applied to the traditional process of information system development. Proper structuring of business rules becomes crucial. .
Simulation of the dynamic behaviour of a permanent magnet linear actuator
Authors: Yatchev Ivan , Gueorgiev Vultchan , Ivanov Racho , Hinov Krastio
Published: October 2011

The paper presents simulation of the dynamics of a permanent magnet linear actuator with soft magnetic mover and relatively long stroke 60 mm. The simulation is carried out using decoupled approach where the magnetic field problem is solved separately from the electric circuit and mechanical motion problems. The obtained results are compared with experiment. .
Analysis of different methods for caller identification sending over internet
Authors: Lebl Aleksandar , Mitic Dragan , Markov Zarko
Published: October 2011

This paper describes different methods of calling subscriber number sending over Internet. The first method uses the coding of signal samples by A-law of compression. In the second one, each bit of this signal is expressed as the telephony event code according to the standardized way of Internet event code presentation. The third one is the new, original method, where the telephony event code presents the whole signal of caller identification. These three methods are compared according to the channel capacity and according to the error probability for the signal sending over Internet. .
Initialization of steady-state security analyses of electric power interconnections
Authors: Popovic Dragan
Published: October 2011

The basic objective of this paper is to present the relevant methodological and practical aspects of two efficient procedures for initialization of steady-state security analyses of electric power interconnection. The first procedure gives the load flow solution for known initial generators scheduling and the second one gives the load-flow solution in conditions of bilateral or multilateral exchange programs realization. Those procedures are fully consistent with the specially developed procedure for steady-state security analysis, which is based on successive solutions of load-flow in characteristic post-dynamic quasi-stationary states, occurring after the considered disturbances. The efficiency of proposed procedures is demonstrated on the example of real electric power interconnection in the Balkan area. .
Non-uniform threshold as an alternative to uniform threshold in denoising in wavelet domain
Authors: Kostov Mitko , Mitrovski Cvetko , Bogdanov Momcilo
Published: October 2011

In this paper we present the advantage of non-uniform over uniform threshold wavelet shrinkage denoising method, applied on noisy signals with signal dependent noise. We illustrate our results by comparing the noise energy after using the both filtration methods on the same set of artificially noise contaminated images. The experiments are made with NPR-QMF filter banks instead with the filter banks that are commonly used in wavelet applications.
Equipotential surface identification of punctual electrically system charges using measurement results
Authors: Golubovic Ljubisa
Published: October 2011

Identification of equipotential surfaces, based on the measurement results and by application of Least Dispersion Volume Method (LDVM) is described in this paper. In a concrete example of two punctual electric charges a suitable methodology for determining corresponded parameters, which characterize the observed equipotential surfaces is presented. Error analyses that take into account the tested parameters are given.
Suboptimal design of turbine governors for low head hydroturbines
Authors: Arnautovic Dusan , Dzepceski Dane
Published: October 2011

The paper considers a low head hydro units control problem by using the modern control theory for turbine governor design. The design of optimal and suboptimal turbine governor is performed by using the optimal control theory and projective controls method. Implementation of modern control theory in contemporary turbine governors is fairly easy to obtain due their realisation in digital technology. Comparison for the closed-loop system dynamic performances, shows that better results are obtained with optimal and suboptimal governors as compared to conventional turbine governors.
Synthesis of reversible circuits for large reversible functions
Authors: Alhagi Nouraddin , Hawash Maher , Perkowski Marek
Published: October 2011

This paper presents a new algorithm MP (multiple pass) to synthesize large reversible binary circuits without ancilla bits. The well-known MMD algorithm for synthesis of reversible circuits requires to store a truth table (or a Reed-Muller - RM transform) as a 2n vector to represent a reversible function of n variables. This representation prohibits synthesis of large functions. However, in MP we do not store such an exponentially growing data structure. The values of minterms are calculated in MP dynamically, one-by-one, from a set of logic equations that specify the reversible circuit to be designed. This allows for synthesis of large scale reversible circuits (30-bits), which is not possible with any existing algorithm. In addition, our unique multi-pass approach where the circuit is synthesized with various, yet specific, minterm orders yields quasi-optimal solution. The algorithm returns a description of the quasi-optimal circuit with respect to gate count or to its 'quantum cost'. Although the synthesis process in MP is relatively slower, the solution is found in real-time for smaller circuits of 8 bits or less.
Real-Time 3D Visualisation for inverted pendulum
Authors: Stojanovic Nikola , Vuckovic Vladan
Published: October 2011

Real-Time 3D Visualisation for Inverted Pendulum is developed by the authors, as the result of some advanced research and real-time 3D simulation of an inverted pendulum. Nowadays, there are some practical applications and robots, controlled mostly using the microprocessor fuzzy controllers, generating the new interest for these machines. Our application has intention to simulate the movements of the inverted pendulum in real time and could interact with user during the generating process. It includes Inverted Pendulum Generator (written in Delphi) and 3d Pendulum Viewer. The application is standalone.
Analysis of induction motor efficiency class change at partial load
Authors: Kostic Miloje
Published: October 2011

Motors with efficiency high values can became inefficient then standard motors when they are lightly loaded. The calculation procedure for the estimation of any part load efficiency when two load points are given is presented in paper. Efficiency dependence is expressed in the form of ? =?N ?k(1-?N), where is magnitude kP = f1(P0,P?N,P/PN), so that changes-deviations of efficiency values compared to rated value (?N) would be explicitly expressed. Based on those deviations, energy efficiency class changes of observed motors are directly identified with load change. Efficiency curve for several motors, with typical shapes, are considered, especially for loads P/PN = 0.50-1.00. These results are shown justification claim that efficiency values at 50% and 75% load shall be stated in the documentation. The users can then select the motor best suited for their application.
Child Independent Mobility in South Africa: The Case of Cape Town and its Hinterland
Authors: Behrens Roger , Muchaka Patrick
Published: October 2011

This article reports upon research conducted amongst schoolchildren aged 7–15 years, and their parents, aimed at exploring independent child mobility in the context of Cape Town and selected towns and rural settlements within its hinterland. The findings of two surveys are discussed. The first was conducted in 2010 and 2011 as part of an international collaborative study on child mobility. The second was conducted in 2010 to assess the prospects of school travel planning practices in the local context. The key findings of the surveys are discussed in terms of how independently mobile children are, how this varies, and how it has changed. It was found that independent mobility varied considerably between wealthy and poor households, and across age and gender. Children from poorer households were heavily reliant on walking (88% share of school trips), and were independently mobile at a relatively young age (67% of seven-year-olds were allowed to travel from school alone). Children from wealthier households appear to have experienced a rapid decline in independent mobility over the past three decades (no seven-year-olds were allowed to travel from school alone), and were heavily reliant on the car (87% share of school trips).
Children's Independent Mobility and Perceptions of Outdoor Environments in Dar Es Salaam City, Tanzania
Authors: Bwire Hannibal
Published: October 2011

This article discusses children's independent mobility (CIM) in Dar es Salaam City. Children's independent mobility refers to the freedom of those under 18 years old to move around in public outdoor environments without adult accompaniment. A number of studies have shown that the neighbourhood environment can be extremely important in enabling children to attain recommended levels of physical activity; the more time children are able to spend in a public outdoor environment the more they are likely to be physically active. Such studies have influenced how researchers measure children mobility, safety, development and well-being. Studies of CIM and related subjects are very important in Africa. Local conditions in support of walking and cycling are poor, which impacts on children's access to education. The study reported here involved the collection of quantitative and qualitative data through the administration of questionnaires completed by both school children aged 7–15 years old, and their parents or guardians. The main focus of this article is on the difference age and gender have on children's independent mobility, children's independent mobility after school hours and during the weekend, and on parents' perception of public outdoor environments. The article concludes with a summary of study findings and policies aimed at improving children's independent mobility and safety and security in public outdoor environments.
Childhood in the Suburbs and the Australian Dream: How Has it Impacted Children's Independent Mobility?
Authors: Rudner Julie , Malone Karen
Published: October 2011

This article presents the research results from a study conducted in New South Wales, Australia about primary school children's independent mobility (CIM), their concerns, and the concerns of their parents. These results are compared with a similar study conducted in 1992. Data were collected using written questionnaires, one for children and one for their parents, distributed via three primary schools. The key findings indicate that school travel has not substantially changed over the past 18 years, although there has been a slight mode shift from walking to school bus travel. Children would like to engage in active transport and have more freedom to do other activities on their own; however, parents restricted CIM based on age, and concerns about traffic and strangers. Although there were localised differences in the survey results, it is hard to determine what influence these factors had on CIM.
Danger from Traffic to Fear of Monkeys: Children's Independent Mobility in Four Diverse Sites in Japan
Authors: Drianda Riela Provi , Kinoshita Isami
Published: October 2011

The study reported on in this article was based on a study of children's independent mobility in four different areas in Japan. Interviews were given to the head principals of the sampled schools, and the Parents and Teachers Association (PTA) members, and questionnaires were sent to a total of 530 children aged 7–15 years and their parents. These were conducted in order to obtain information regarding the possibilities for children to engage in independent mobility within a variety of community settings. The findings showed that many young children in Japan are allowed by their parents to travel to and from school alone. The older the children were the more they were granted many varied licenses and freedoms for independent mobility. However, a change in children's attitudes toward the home-school journey was identified in this study. While it is a common norm in Japan that children should go to school on foot or by public transportation, the findings showed that some children have started to rely on private cars as the main transportation to travel to and return from school. In particular this was evident with children who live in small towns and rural areas. This study reveals that in a diverse geographical environment, the extent to which Japanese children can engage in independent mobility is varied. Overall, for children living in the capital city of Tokyo it appears they have more freedom to engage in independent mobility than their counterparts in suburban, small town and rural areas.
Global Perspectives on Children's Independent Mobility: A Socio-Cultural Comparison and Theoretical Discussion of Children's Lives in Four Countries in Asia and Africa
Authors: Malone Karen , Rudner Julie
Published: October 2011

The article provides a comparative analysis of children's independent mobility in four countries – South Africa, Tanzania, Japan and Australia. The authors discuss key findings across the four study sites and illustrate the contextually bound nuances connected to the data at the community level. The data illustrate that while Japanese children have the most independence generally, Japanese children who live in a small town outside of a main city centre have significantly lower mobility than their city counterparts, and levels of car use for driving children to school are similar to levels in Australia. The results also reveal that while children in South Africa generally look to be more independent, have fewer restrictions and are accompanied less by parents than children in Australia (which appears to have the highest rate of accompaniment), the community-wide data illustrate that children living in the high-income city communities have the least amount of independence of all sites in the four countries, with travel to school by car as high as 87%. Additionally, the research illustrates that age is not a clear determinant of a growing increase in independence and mobility in communities. An inspection of the data reveals possibilities for considering the heterogeneous perspective of childhood where the intersection of children's locales and how children traverse them is as significant as the aggregated data that provide universal notions of the childhood experience. The final discussions provide some opportunities to consider Prout's introduction of a life course approach for reconceptualising children and childhood, which he believes allows for a multiplicity and complexity of childhoods. This concept is seen to be helpful when considering how to include global perspectives in children's independent mobility without universalising children's life experience.
Higher Education as Commodity or Space for Learning: Modelling Contradictions in Educational Practices
Authors: Nilsson Monica , Wihlborg Monne
Published: October 2011

In this article the authors reflect upon and critically examine signs of a contradiction in higher education which they discuss in terms of the tension between ‘use value’ and ‘exchange value’. Use value here represents learning as something valuable ‘in itself’, whereas exchange value represents learning as an achievement of grades and credits to be ‘traded’ on a market. Their aim in this article is to present a model based on the concepts of use value and exchange value, clarifying how they might relate to surface and deep approaches to learning. The model is suggested as a device to explore and analyse local tensions emanating from the contradiction. They also argue in favour of a pedagogical philosophy based on the notion of community.
Managerialism and Myth: The Legitimacy of Management in Higher Education and the Consequences of its Decline
Authors: Harris David
Published: October 2011

Using a Habermasian framework initially, the article discusses changes in the working lifeworld of academics as a result of colonisation by system imperatives, understood in the sense of a growing instrumentalism to control teaching, learning, assessment and course design. At the same time, ‘crisis tendencies' affecting legitimation can also be detected. Substantive issues include the role of mythical accounts of organisations, both official managerial ones expressed in Change Academy documents, for example, and unofficial ones expressed surreptitiously by academic staff. These include stories about instrumental coping with quality regimes, scathing commentaries on various aspects of managerialism, and a tendency to ‘teach to the test’ (matching student instrumentalism) in order to square the circle of widening intakes without extra resources while maintaining ‘standards’.
Evolution of Bridge Technology
Authors: Tang Man-Chung
Published: October 2011

The evolution of bridge technology can be divided into two major eras: The Arch Era, from 2000 BC to the end of 18th century, was dominated by the Roman structures. They were practically all stone arches. The Contemporary Era that followed and continues today, flourished after steel was commercially available as a construction material in the mid 19th century. All modern bridge types including girder bridges, cable-stayed bridges, suspension bridges and arch bridges, especially those with larger spans, have been possible only because of the high strength of steel, both in compression and in tension.
Life Cycle Management of Infrastructures: towards an integrated approach of design, construction and maintenance
Authors: van der Horst Aad
Published: October 2011

This paper presents principles of life cycle optimization from an engineering point of view. The optimization is reached through interaction between the disciplines of design, construction and maintenance. Process aspects, tools and criteria are discussed with focus on the reliability of these aspects.
Traffic projects 'German unity' – a success story on the fast development of infrastructure in the newly-formed German states
Authors: Lütke-Daldrup Engelbert , Naumann Joachim
Published: October 2011

On 3 October 1990, reunification of the two Germanys, which had long been hoped for on both sides of the border, became reality. After the initial euphoria, however, it soon became obvious that this was going to be a great challenge and would require major efforts by all those involved. Here, the rapid development and upgrading of the transport infrastructure in the new federal states played a key role, because this was an important prerequisite for the necessary economic upturn and the progressive approximation of living standards in Eastern and Western Germany. A major foundation was created for this with the decision to give priority to the construction of the “German Unity Transport Projects”, and this has been crucial in helping the two Germanys to grow together.
Congestion taxes: a way of financing new infrastructure
Authors: Rydberg Forssbeck Lahja , Karlsson Mats , Höök Birger
Published: October 2011

The present volume of traffic on the main thoroughfares in Stockholm often greatly exceeds the capacity for which they were originally built. In other words, the Stockholm traffic system has almost reached its maximum capacity. A lack of space and money makes it difficult to build new roads. The actual situation creates a need of using existing road system more efficient. To change traffic flows and road usage a congestion tax system was introduced in Stockholm inner city area and a trial operation was carried out between 3 January and 31 July 2006. The Swedish Road Administration was commissioned by the Government for the implementation. An extensive, sophisticated technical system was developed.
The National Motorway Construction Programme in the Republic of Slovenia
Authors: Marc Ksenija
Published: October 2011

The National Motorway Construction Programme in the Republic of Slovenia was enacted in 1995 by the National Assembly in order to provide an adequate and efficient road system, improve road safety, ensure integration with the broader European area, and to boost economic growth. Other structural goals to be met were: maximize economic effects and minimize the pollution of the environment, ensure greater economic, social and tourist benefits, and at the same time maintain the existing motorway infrastructure.
Public Private Partnership Approach to an Integrated Life-Cycle Management of Highway Infrastructure in Hong Kong
Authors: So Kevin K. L. , Cheung Moe M. S.
Published: October 2011

Transport infrastructure system is central to economic activities and important to economic growth. The rapid economic growth of Hong Kong, especially in last two decades, leads to high demands of a comprehensive and effective highway networks. Conventional procurement approach without the integration of probabilistic life cycle cost model induces substantial long term maintenance cost. The main idea of this paper is to develop a research framework for predicting the service life by using appropriate corrosion deteriorating model on reinforced concrete structures. The deteriorating model will then be integrated into life-cycle cost analysis in dealing with long term maintenance and repair strategy. Once deteriorating and life-cycle cost models of highway structures have been established, proper public private partnership procurement strategies and associated financing method and project period determination could be established.