Search results for: Volume fraction

Authors: Jiri Barta, Jiri F. Urbanek

Abstract:

This paper deals with a protection of the national and European infrastructure. It is issue nowadays. The paper deals with the perspectives and possibilities of "smart solutions" to critical infrastructure protection. The research project deals with computers aided technologies are used from the perspective of new, better protection of selected infrastructure objects. Protection is focused on communication and information channels. These communication and information channels are very important for the functioning of the system of protection of critical infrastructure elements.

Keywords: Interoperability, Communication systems, Controlling Process, Critical Infrastructure, Crisis Workplaces. Continuity.

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Authors: M. Saeedi, R. Wuchner, K.-U. Bletzinger

Abstract:

In order to study the aerodynamic performance of a semi-flexible membrane wing, Fluid-Structure Interaction simulations have been performed. The fluid problem has been modeled using two different approaches which are the vortex panel method and the numerical solution of the Navier-Stokes equations. Nonlinear analysis of the structural problem is performed using the Finite Element Method. Comparison between the two fluid solvers has been made. Aerodynamic performance of the wing is discussed regarding its lift and drag coefficients and they are compared with those of the equivalent rigid wing.

Keywords: CFD, FSI, Membrane wing, Vortex panel method.

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Authors: Lili Wang, Meng Hu

Abstract:

In this paper, a class of recurrent neural networks (RNNs) with variable delays are studied on almost periodic time scales, some sufficient conditions are established for the existence and global exponential stability of the almost periodic solution. These results have important leading significance in designs and applications of RNNs. Finally, two examples and numerical simulations are presented to illustrate the feasibility and effectiveness of the results.

Keywords: Recurrent neural network, Almost periodic solution, Global exponential stability, Time scale.

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Authors: S. Sivakumar, Ravikiran Sangras, Vasudevan Raghavan

Abstract:

In this work, stationary hot-wire measurements are carried out to investigate the characteristics of a round free jet in its potential core region (0 ≤ x/d ≤ 10). Measurements are carried out on an incompressible round jet for a range of Reynolds numbers from 4000 to 8000, calculated based on the jet exit mean velocity and the nozzle diameter. The effect of flow velocity on the development characteristics of the jet in the core region is analyzed. Timeaveraged statistics, spectra of velocity and its higher order moments are presented and explained.

Keywords: Contoured nozzle, hot-wire anemometer, Reynolds number, velocity fluctuations, velocity spectra.

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Authors: T. Abdelkrim, K. Benamrane, B. Bezza, Aeh Benkhelifa, A. Borni

Abstract:

This paper proposes a regulation method of back-to-back connected three-level converters in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of three-level PWM rectifier. In the second part, three-level NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.

Keywords: Back-to-back connection, Feedback control, Neutral-point balance, Three-level converter, Torque ripple.

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Authors: Ahmet Tekcan

Abstract:

Let X be a connected space, X be a space, let p : X -→ X be a continuous map and let (X, p) be a covering space of X. In the first section we give some preliminaries from covering spaces and their automorphism groups. In the second section we derive some algebraic properties of both universal and regular covering spaces (X, p) of X and also their automorphism groups A(X, p).

Keywords: covering space, universal covering, regular covering, fundamental group, automorphism group.

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Authors: Bo Bae Song, Byung Seok Lee, Hyun Young Kim, Chung Kwang Lee, Yong Seo Koo

Abstract:

This paper proposed a silicon controller rectifier (SCR) based ESD protection device to protect low voltage ESD for integrated circuit. The proposed ESD protection device has low trigger voltage and high holding voltage compared with conventional SCR-based ESD protection devices. The proposed ESD protection circuit is verified and compared by TCAD simulation. This paper verified effective low voltage ESD characteristics with low trigger voltage of 5.79V and high holding voltage of 3.5V through optimization depending on design variables (D1, D2, D3 and D4).

Keywords: ESD, SCR, Holding voltage, Latch-up.

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Authors: Young-Min Ko, Seung-Jun Yu, Chang-Bin Ha, Hyoung-Kyu Song

Abstract:

In a wireless communication system, the failure of base station can result in a communication disruption in the cell. This paper proposes a way to deal with the failure of base station in a wireless communication system based on OFDM. Cooperative communication of the adjacent base stations can be a solution of the problem. High performance is obtained by the configuration of transmission signals which is applied CDD scheme in the cooperative communication. The Cooperative scheme can be a e ective solution in case of the particular situation.

Keywords: Base station, CDD, OFDM, Diversity gain, MIMO.

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Authors: Gizem Intepe, Tufan Koc

Abstract:

S-Curves are commonly used in technology forecasting. They show the paths of product performance in relation to time or investment in R&D. It is a useful tool to describe the inflection points and the limit of improvement of a technology. Companies use this information to base their innovation strategies. However inadequate use and some limitations of this technique lead to problems in decision making. In this paper first technology forecasting and its importance for company level strategies will be discussed. Secondly the S-Curve and its place among other forecasting techniques will be introduced. Thirdly its use in technology forecasting will be discussed based on its advantages, disadvantages and limitations. Finally an application of S-curve on 3D TV technology using patent data will also be presented and the results will be discussed.

Keywords: Patent analysis, Technological forecasting. S curves, 3D TV

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Authors: S. Banerjee

Abstract:

The paper describes design of an ontology in the financial domain for mutual funds. The design of this ontology consists of four steps, namely, specification, knowledge acquisition, implementation and semantic query. Specification includes a description of the taxonomy and different types mutual funds and their scope. Knowledge acquisition involves the information extraction from heterogeneous resources. Implementation describes the conceptualization and encoding of this data. Finally, semantic query permits complex queries to integrated data, mapping of these database entities to ontological concepts.

Keywords: Ontology, Semantic Web, Mutual Funds.

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Authors: Tomislav Stambolic, Anton Causevski

Abstract:

The deficit of power supply in Macedonia is almost 30% or reached up to 3000 GWh in a year. The existing thermal and hydro power plants are not enough to cover the power and energy, so the import increases every year. Therefore, in order to have more domestic energy supply, the new trends in renewable and energy efficiency should be implemented in power sector. The paper gives some perspectives for development of the power system in Macedonia, taking into account the growth of electricity demand and in the same time with implementation of renewable and energy efficiency. The development of power system is made for the period up to 2030 with the period of every 5 years.

Keywords: Energy, Power System, Renewable, Efficiency

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Authors: M. Bakhtaoui, L. Merahi

Abstract:

The reliability of the filtered HVBK model is now investigated via some large eddy simulations (LES) of freely decaying isotropic superfluid turbulence. For homogeneous turbulence at very high Reynolds numbers, comparison of the terms in the spectral kinetic energy budget equation indicates, in the energy-containing range, that the production and energy transfer effects become significant except for dissipation. In the inertial range, where the two fluids are perfectly locked, the mutual friction maybe neglected with respect to other terms. Also, the LES results for the other terms of the energy balance are presented.

Keywords: Superfluid turbulence, HVBK, Energy budget, Large Eddy Simulation.

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Authors: A. Ramdane, F.Naceri, S. Ramdane

Abstract:

in this work, we present a new strategy of direct adaptive control denoted: Extended minimal controller synthesis (EMCS). This algorithm is designed for an induction motor, which includes both electrical and mechanical dynamics under the assumptions of linear magnetic circuits. The main motivation of the EMCS control is to enhance the robustness of the MRAC algorithms, i.e. the rejection of bounded effects of rapidly varying external disturbances.

Keywords: Adaptive Control, Simple model reference adaptive control (SMRAC), Extended Minimal Controller synthesis (EMCS), Induction Motor (IM)

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Authors: R. Suszynski, K. Wawryn, R. Wirski

Abstract:

The new concept of two–dimensional (2D) image processing implementation for auto-guiding system is shown in this paper. It is dedicated to astrophotography and operates with astronomy CCD guide cameras or with self-guided dual-detector CCD cameras and ST4 compatible equatorial mounts. This idea was verified by MATLAB model, which was used to test all procedures and data conversions. Next the circuit prototype was implemented at Altera MAX II CPLD device and tested for real astronomical object images. The digital processing speed of CPLD prototype board was sufficient for correct equatorial mount guiding in real-time system.

Keywords: DSO astrophotography, image processing, twodimensionalconvolution method, two-dimensional filtering.

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Authors: Zelal Çinar

Abstract:

This paper claims that architecture is a contingent discipline, despite the fact that its contingency has long been denied through a retreat to Vitruvian writing. It is evident that contingency is rejected not only by architecture but also by modernity as a whole. Vitruvius attempted to cover the entire field of architecture in a systematic form in order to bring the whole body of this great discipline to a complete order. The legacy of his theory hitherto lasted not only that it is the only major work on the architecture of Classical Antiquity to have survived, but also that its conformity with the project of modernity. In the scope of the paper, it will be argued that contingency should be taken into account rather than avoided as a potential threat. 

Keywords: Architecture, contingency, modernity, Vitruvius.

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Authors: Michal Spilacek, Marian Brazdil, Otakar Stelcl, Jiri Pospisil

Abstract:

This paper shows an experimental testing of a small unit for combustion of solid fuels, such as charcoal and wood logs, that can provide electricity. One of the concepts is that the unit does not require qualified personnel for its operation. The unit itself is composed of two main parts. The design requires a heat producing stove and electricity producing thermoelectric generator. After the construction the unit was tested and the results show that the emission release is within the legislative requirements for emission production and environmental protection. That qualifies such unit for indoor application.

Keywords: Micro-cogeneration, thermoelectric generator, biomass combustion, wood stove.

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Authors: Sh. Hamada, N. Burtebayev, N. Amangeldi, A. Amar

Abstract:

An experiment was performed with a 24.5 MeV 14N beam on a 12C target in the cyclotron DC-60 located in Astana, Kazakhstan, to study the elastic scattering of 14N on 12C; the scattering was also analyzed at different energies for tracking the phenomenon of remarkable structure at large angles. Its aims were to extend the measurements to very large angles, and attempt to uniquely identify the elastic scattering potential. Good agreement between the theoretical and experimental data has been obtained with suitable optical potential parameters. Optical model calculations with l -dependent imaginary potentials were also applied to the data and relatively good agreement was found.

Keywords: Optical Potential Codes, Elastic Scattering, SPIVALCode.

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Authors: Derya Burcu Ozkan, Onur Kiziler, Duriye Bilge

Abstract:

Cogeneration may be defined as a system which contains electricity production and regain of the thermo value of exhaust gases simultaneously. The examination is based on the data-s of an active cogeneration plant. This study, it is aimed to determine which component of the system should be revised first to raise the efficiency and decrease the loss of exergy. For this purpose, second law analysis of thermodynamics is applied to each component due to consider the effects of environmental conditions and take the quality of energy into consideration as well as the quantity of it. The exergy balance equations are produced and exergy loss is calculated for each component. 44,44 % loss of exergy in heat exchanger, 29,59 % in combustion chamber, 18,68 % in steam boiler, 5,25 % in gas turbine and 2,03 % in compressor is calculated.

Keywords: Cogeneration, Exergy loss, Second law analysis

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Authors: Alejandro Gomez Suarez, H. Srikanth Kamath

Abstract:

In this paper, SFQ (Start Time Fair Queuing) algorithm is analyzed when this is applied in computer networks to know what kind of behavior the traffic in the net has when different data sources are managed by the scheduler. Using the NS2 software the computer networks were simulated to be able to get the graphs showing the performance of the scheduler. Different traffic sources were introduced in the scripts, trying to establish the real scenario. Finally the results were that depending on the data source, the traffic can be affected in different levels, when Constant Bite Rate is applied, the scheduler ensures a constant level of data sent and received, but the truth is that in the real life it is impossible to ensure a level that resists the changes in work load.

Keywords: Cbq, Cbr, Nam, Ns2.

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Authors: Elizabeth Downs, Judith Repman, Kenneth Clark

Abstract:

This paper describes the evolution of strategies to evaluate ePortfolios in an online Master-s of Education (M.Ed.) degree in Instructional Technology. The ePortfolios are required as a culminating activity for students in the program. By using Web 2.0 tools to develop the ePortfolios, students are able to showcase their technical skills, integrate national standards, demonstrate their professional understandings, and reflect on their individual learning. Faculty have created assessment strategies to evaluate student achievement of these skills. To further develop ePortfolios as a tool promoting authentic learning, faculty are moving toward integrating transparency as part of the evaluation process.

Keywords: e-learning evaluation, ePortfolios, transparency, Web 2.0

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Authors: Hae-Soon Ahn, Eun-Jun Yoon

Abstract:

With the rapid development of wireless mobile communication, applications for mobile devices must focus on network security. In 2008, Chang-Chang proposed security improvements on the Lu et al.-s elliptic curve authentication key agreement protocol for wireless mobile networks. However, this paper shows that Chang- Chang-s improved protocol is still vulnerable to off-line password guessing attacks unlike their claims.

Keywords: Authentication, key agreement, wireless mobile networks, elliptic curve, password guessing attacks.

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Authors: Takahiro Togawa, Nguyen Huu Phuc, Shigeyuki Haruyama, Oke Oktavianty

Abstract:

Our research focuses on a framework which analyses the relationship between product/process architecture, manufacturing organizational capability and manufacturing "implicit competitiveness" in order to improve manufacturing implicit competitiveness. We found that 1) there is a relationship between architecture-based manufacturing organizational capability and manufacturing implicit competitiveness, and 2) analysis and measures conducted in manufacturing organizational capability proved effective to improve manufacturing implicit competitiveness.

Keywords: Implicit competitiveness, QCD, Monozukuri capability.

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Authors: Pranam Janney, Sridhar G, Sridhar V.

Abstract:

Content-Based Image Retrieval has been a major area of research in recent years. Efficient image retrieval with high precision would require an approach which combines usage of both the color and texture features of the image. In this paper we propose a method for enhancing the capabilities of texture based feature extraction and further demonstrate the use of these enhanced texture features in Texture-Based Color Image Retrieval.

Keywords: Image retrieval, texture feature extraction, color extraction

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Authors: H. B. Kekre, Tanuja K. Sarode

Abstract:

This paper presents a very simple and efficient algorithm for codebook search, which reduces a great deal of computation as compared to the full codebook search. The algorithm is based on sorting and centroid technique for search. The results table shows the effectiveness of the proposed algorithm in terms of computational complexity. In this paper we also introduce a new performance parameter named as Average fractional change in pixel value as we feel that it gives better understanding of the closeness of the image since it is related to the perception. This new performance parameter takes into consideration the average fractional change in each pixel value.

Keywords: Vector Quantization, Data Compression, Encoding, Searching.

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Authors: Mauricio Pe˜na, Adriana Luna, Carol Rodr´ıguez

Abstract:

In the following article we begin from a multi-parameter unstable nonlinear model of a Quadrotor. We design a control to stabilize and assure the attitude of the device, starting off a linearized system at the equilibrium point of the null angles of Euler (hover), which provides us a control with limited capacities at small angles of rotation of the vehicle in three dimensions. In order to clear this obstacle, we propose the identification of models in different angles by means of simulations and the design of a controller specifically implemented for the identification task, that in future works will allow the development of controllers according to fast and agile angles of Euler for Quadrotor.

Keywords: Quadrotor, model, control, identification.

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Authors: S. Park, J. Hwang, K. Rou, E. Kim

Abstract:

In this paper, we consider a new particle filter inspired by biological evolution. In the standard particle filter, a resampling scheme is used to decrease the degeneracy phenomenon and improve estimation performance. Unfortunately, however, it could cause the undesired the particle deprivation problem, as well. In order to overcome this problem of the particle filter, we propose a novel filtering method called the genetic filter. In the proposed filter, we embed the genetic algorithm into the particle filter and overcome the problems of the standard particle filter. The validity of the proposed method is demonstrated by computer simulation.

Keywords: Particle filter, genetic algorithm, evolutionary algorithm.

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Authors: Jamal Amani Rad, Kourosh Parand

Abstract:

In this paper, we have applied the homotopy perturbation method (HPM) for obtaining the analytical solution of unsteady flow of gas through a porous medium and we have also compared the findings of this research with some other analytical results. Results showed a very good agreement between results of HPM and the numerical solutions of the problem rather than other analytical solutions which have previously been applied. The results of homotopy perturbation method are of high accuracy and the method is very effective and succinct.

Keywords: Unsteady gas equation, Homotopy perturbation method(HPM), Porous medium, Nonlinear ODE

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Authors: A. A. Penin

Abstract:

Requirements that should be met when determining the regimes of circuits with variable elements are formulated. The interpretation of the variations in the regimes, based on projective geometry, enables adequate expressions for determining and comparing the regimes to be derived. It is proposed to use as the parameters of a generalized equivalent generator of an active two-pole with changeable resistor such load current and voltage which provide the current through this resistor equal to zero.

Keywords: Equivalent generator, geometric circuits theory, circuits regimes, load characteristics, variable elements.

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Authors: A. Bekbaev, M. Dzhamanbaev, R. Abitaeva, A. Karbozova, G. Nabyeva

Abstract:

In this paper, the regression dependence of dancing intensity from wind speed and length of span was established due to the statistic data obtained from multi-year observations on line wires dancing accumulated by power systems of Kazakhstan and the Russian Federation. The lower and upper limitations of the equations parameters were estimated, as well as the adequacy of the regression model. The constructed model will be used in research of dancing phenomena for the development of methods and means of protection against dancing and for zoning plan of the territories of line wire dancing.

Keywords: Power lines, line wire dancing, dancing intensity, regression equation, dancing area intensity.

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Authors: Farhad Kolahan, M. Hossein Abolbashari, Samaeddin Mohitzadeh

Abstract:

Several methods are available for weight and shape optimization of structures, among which Evolutionary Structural Optimization (ESO) is one of the most widely used methods. In ESO, however, the optimization criterion is completely case-dependent. Moreover, only the improving solutions are accepted during the search. In this paper a Simulated Annealing (SA) algorithm is used for structural optimization problem. This algorithm differs from other random search methods by accepting non-improving solutions. The implementation of SA algorithm is done through reducing the number of finite element analyses (function evaluations). Computational results show that SA can efficiently and effectively solve such optimization problems within short search time.

Keywords: Simulated annealing, Structural optimization, Compliance, C.V. product.

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