Search results for: stability and degree
1153 On Thermal Instabilities in a Viscoelastic Fluid Subject to Internal Heat Generation
Authors: Donna M. G. Comissiong, Tyrone D. Dass, Harold Ramkissoon, Alana R. Sankar
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The B'enard-Marangoni thermal instability problem for a viscoelastic Jeffreys- fluid layer with internal heat generation is investigated. The fluid layer is bounded above by a realistic free deformable surface and by a plane surface below. Our analysis shows that while the internal heat generation and the relaxation time both destabilize the fluid layer, its stability may be enhanced by an increased retardation time.Keywords: Viscoelastic fluid, Jeffreys' model, Maxwell model, internal heat generation, retardation time, relaxation time.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16561152 Experimental Study of Submersible Jet on Flow Hydraulic Parameters
Authors: Mohsen Solimani Babarsad, Habib Musavi Jahromi
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Behavior of turbulent jet is relying on jet parameters, environmental and geometric parameters. In this research, it has attempt to Study effect of jet parameters of internal angle on maximum effective length and velocity on centerline from nozzle experimentally. Toward this end, four internal angles 30, 45, 60 and 90-degree are considered for this study in a flume with 600cm as long, 100cm as high and 150cm in width. Various discharges were used to evaluate effective length for a wide range of densimetric Froude numbers F0, from 17.9 to 39.4 that is defined at the nozzle. As a result, It is revealed that both velocity on centerline and effective length decreases when nozzle angle decreased from 90° to 30°. The results show that, for all range of Fr0 the Um/U0 ratio for nozzle with α=90° on centerline increases 20% - 27% than nozzle with α=30° that has lowest velocity on centerline than other nozzle.
Keywords: Turbulent jet, velocity, effective length, Froude number.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15451151 Several Spectrally Non-Arbitrary Ray Patterns of Order 4
Authors: Ling Zhang, Feng Liu
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A matrix is called a ray pattern matrix if its entries are either 0 or a ray in complex plane which originates from 0. A ray pattern A of order n is called spectrally arbitrary if the complex matrices in the ray pattern class of A give rise to all possible nth degree complex polynomial. Otherwise, it is said to be spectrally non-arbitrary ray pattern. We call that a spectrally arbitrary ray pattern A of order n is minimally spectrally arbitrary if any nonzero entry of A is replaced, then A is not spectrally arbitrary. In this paper, we find that is not spectrally arbitrary when n equals to 4 for any θ which is greater than or equal to 0 and less than or equal to n. In this article, we give several ray patterns A(θ) of order n that are not spectrally arbitrary for some θ which is greater than or equal to 0 and less than or equal to n. by using the nilpotent-Jacobi method. One example is given in our paper.
Keywords: Spectrally arbitrary, Nilpotent matrix, Ray patterns, sign patterns.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 6121150 Implementation of a Web-Based Wireless ECG Measuring and Recording System
Authors: Onder Yakut, Serdar Solak, Emine Dogru Bolat
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Measuring the Electrocardiogram (ECG) signal is an essential process for the diagnosis of the heart diseases. The ECG signal has the information of the degree of how much the heart performs its functions. In medical diagnosis and treatment systems, Decision Support Systems processing the ECG signal are being developed for the use of clinicians while medical examination. In this study, a modular wireless ECG (WECG) measuring and recording system using a single board computer and e-Health sensor platform is developed. In this designed modular system, after the ECG signal is taken from the body surface by the electrodes first, it is filtered and converted to digital form. Then, it is recorded to the health database using Wi-Fi communication technology. The real time access of the ECG data is provided through the internet utilizing the developed web interface.Keywords: ECG, e-health sensor shield, raspberry Pi, wifi technology.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 30061149 Simulating Pathogen Transport with in a Naturally Ventilated Hospital Ward
Authors: C. A. Gilkeson, C. J. Noakes, P. A. Sleigh, M. A. I. Khan, M. A. Camargo-Valero
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Understanding how airborne pathogens are transported through hospital wards is essential for determining the infection risk to patients and healthcare workers. This study utilizes Computational Fluid Dynamics (CFD) simulations to explore possible pathogen transport within a six-bed partitioned Nightingalestyle hospital ward. Grid independence of a ward model was addressed using the Grid Convergence Index (GCI) from solutions obtained using three fullystructured grids. Pathogens were simulated using source terms in conjunction with a scalar transport equation and a RANS turbulence model. Errors were found to be less than 4% in the calculation of air velocities but an average of 13% was seen in the scalar field. A parametric study of variations in the pathogen release point illustrated that its distribution is strongly influenced by the local velocity field and the degree of air mixing present.Keywords: Natural, Ventilation, Pathogen, Transport
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 14931148 Cyber Security in Nigeria: A Collaboration between Communities and Professionals
Authors: K. Alese Boniface, K. Adu Michael, K. Owa Victor
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Security can be defined as the degree of resistance to, or protection from harm. It applies to any vulnerable and valuable assets, such as persons, dwellings, communities, nations or organizations. Cybercrime is any crime committed or facilitated via the Internet. It is any criminal activity involving computers and networks. It can range from fraud to unsolicited emails (spam). It includes the distant theft of government or corporate secrets through criminal trespass into remote systems around the globe. Nigeria like any other nations of the world is currently having her own share of the menace that has been used even as tools by terrorists. This paper is an attempt at presenting cyber security as an issue that requires a coordinated national response. It also acknowledges and advocates the key roles to be played by stakeholders and the importance of forging strong partnerships to prevent and tackle cybercrime in Nigeria.
Keywords: Security, Cybercrime, Internet, Government, Stakeholders, Partnerships.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 28171147 Performance Evaluation of Popular Hash Functions
Authors: Sheena Mathew, K. Poulose Jacob
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This paper describes the results of an extensive study and comparison of popular hash functions SHA-1, SHA-256, RIPEMD-160 and RIPEMD-320 with JERIM-320, a 320-bit hash function. The compression functions of hash functions like SHA-1 and SHA-256 are designed using serial successive iteration whereas those like RIPEMD-160 and RIPEMD-320 are designed using two parallel lines of message processing. JERIM-320 uses four parallel lines of message processing resulting in higher level of security than other hash functions at comparable speed and memory requirement. The performance evaluation of these methods has been done by using practical implementation and also by using step computation methods. JERIM-320 proves to be secure and ensures the integrity of messages at a higher degree. The focus of this work is to establish JERIM-320 as an alternative of the present day hash functions for the fast growing internet applications.Keywords: Cryptography, Hash function, JERIM-320, Messageintegrity
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26411146 Factors Related to the Satisfaction of Car Consumers
Authors: Somtop Keawchuer
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The objective of this research was to study the factors related to the satisfaction of consumers who purchased a Toyota SUV Fortuner. This paper was a survey data which collected 400 samples from 65 car dealerships. The survey was conducted mainly in Bangkok, Thailand. The statistics utilized in this paper included percentage, mean, standard deviation and Pearson Product-Moment. The findings revealed that the majority of respondent were male with an undergraduate degree, married and live together. The average income of the respondents was between 20,001 - 30,000 baht. Most of them worked for private companies. Most of them had a family with the average of 4 members. The hypotheses testing revealed that the factors of marketing mix in terms of product (ability, gas mileage, and safety) were related to overall satisfaction at the medium level. However, the findings also revealed that the factors of marketing mix in terms of product (image), price, and promotion, and service center were related to the overall satisfaction at the low level.
Keywords: Car Consumers, Factors related, Overall Satisfaction.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18001145 Robust Nonlinear Control of a Miniature Autonomous Helicopter using Sliding Mode Control Structure
Authors: H. Ifassiouen, M. Guisser, H.Medromi
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This paper presents an investigation into the design of a flight control system, using a robust sliding mode control structure, designed using the exact feedback linearization procedure of the dynamic of a small-size autonomous helicopter in hover. The robustness of the controller in the context of stabilization and trajectory tracking with respect to small body forces and air resistance on the main and tail rotor, is analytically proved using Lyapunov approach. Some simulation results are presented to illustrate the performance and robustness of such controller in the presence of small body forces and air resistance.
Keywords: Robust control, sliding mode, stability, Lyapunovapproach.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18031144 Management of English Language Teaching in Higher Education
Authors: Vishal D. Pandya
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A great deal of perceptible change has been taking place in the way our institutions of higher learning are being managed in India today. It is believed that managers, whose intuition proves to be accurate, often tend to be the most successful, and this is what makes them almost like entrepreneurs. A certain entrepreneurial spirit is what is expected and requires a degree of insight of the manager to be successful depending upon the situational and more importantly, the heterogeneity as well as the socio-cultural aspect. Teachers in Higher Education have to play multiple roles to make sure that the Learning-Teaching process becomes effective in the real sense of the term. This paper makes an effort to take a close look at that, especially in the context of the management of English language teaching in Higher Education and, therefore, focuses on the management of English language teaching in higher education by understanding target situation analyses at the socio-cultural level.
Keywords: Management, language teaching, English language teaching, higher education.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18941143 Two Spherical Three Degrees of Freedom Parallel Robots 3-RCC and 3-RRS Static Analysis
Authors: Alireza Abbasi Moshaii, Mehdi Tale Masouleh, Esmail Zarezadeh, Kamran Farajzadeh
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The main purpose of this study is static analysis of two three-degree of freedom parallel mechanisms: 3-RCC and 3- RRS. Geometry of these mechanisms is expressed and static equilibrium equations are derived for the whole chains. For these mechanisms due to the equal number of equations and unknowns, the solution is as same as 3-RCC mechanism. A mathematical software is used to solve the equations. In order to prove the results obtained from solving the equations of mechanisms, the CAD model of these robots has been simulated and their static is analysed in ADAMS software. Due to symmetrical geometry of the mechanisms, the force and external torque acting on the end-effecter have been considered asymmetric to prove the generality of the solution method. Finally, the results of both softwares, for both mechanisms are extracted and compared as graphs. The good achieved comparison between the results indicates the accuracy of the analysis.Keywords: Robotic, Static analysis, 3-RCC, 3-RRS.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19691142 Computing a Time Based Effective Radius-of-Curvature for Roadways
Authors: Gary D. Cantrell, E. Alex Baylot
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The radius-of-curvature (ROC) defines the degree of curvature along the centerline of a roadway whereby a travelling vehicle must follow. Roadway designs must encompass ROC in mitigating the cost of earthwork associated with construction while also allowing vehicles to travel at maximum allowable design speeds. Thus, a road will tend to follow natural topography where possible, but curvature must also be optimized to permit fast, but safe vehicle speeds. The more severe the curvature of the road, the slower the permissible vehicle speed. For route planning, whether for urban settings, emergency operations, or even parcel delivery, ROC is a necessary attribute of road arcs for computing travel time. It is extremely rare for a geo-spatial database to contain ROC. This paper will present a procedure and mathematical algorithm to calculate and assign ROC to a segment pair and/or polyline.Keywords: linear features, radius-of-curvature, roads, routing, traffic, turning
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 15941141 A Remote Sensing Approach to Calculate Population Using Roads Network Data in Lebanon
Authors: Kamel Allaw, Jocelyne Adjizian Gerard, Makram Chehayeb, Nada Badaro Saliba
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In developing countries, such as Lebanon, the demographic data are hardly available due to the absence of the mechanization of population system. The aim of this study is to evaluate, using only remote sensing data, the correlations between the number of population and the characteristics of roads network (length of primary roads, length of secondary roads, total length of roads, density and percentage of roads and the number of intersections). In order to find the influence of the different factors on the demographic data, we studied the degree of correlation between each factor and the number of population. The results of this study have shown a strong correlation between the number of population and the density of roads and the number of intersections.
Keywords: Population, road network, statistical correlations, remote sensing.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 9961140 Thermodynamic Study of Hot Potassium Carbonate Solution Using Aspen Plus
Authors: O. Eisa, M. Shuhaimi
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This paper presents a study on the thermodynamics and transport properties of hot potassium carbonate aqueous system (HPC) using electrolyte non-random two liquid, (ELECNRTL) model. The operation conditions are varied to determine the system liquid phase stability range at the standard and critical conditions. A case study involving 30 wt% K2CO3, H2O standard system at pressure of 1 bar and temperature range from 280.15 to 366.15 K has been studied. The estimated solubility index, viscosity, water activity, and density which obtained from the simulation showed a good agreement with the experimental work. Furthermore, the saturation temperature of the solution has been estimated.Keywords: Viscosity, Saturation index, Activity coefficient, Density.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 53911139 The Effect of Screw Parameters on Pullout Strength of Screw Fixation in Cervical Spine
Authors: S. Ritddech, P. Aroonjarattham, K. Aroonjarattham
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The pullout strength had an effect on the stability of plate screw fixation when inserted in the cervical spine. Nine different titanium alloy bone screws were used to test the pullout strength through finite element analysis. The result showed that the Moss Miami I can bear the highest pullout force at 1,075 N, which causes the maximum von Mises stress at 858.87 MPa, a value over the yield strength of titanium. The bone screw should have large outer diameter, core diameter and proximal root radius to increase the pullout strength.
Keywords: Pullout strength, Screw parameter, Cervical spine, Finite element analysis.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 31561138 On the Numerical and Experimental Analysis of Internal Pressure in Air Bearings
Authors: Abdurrahim Dal, Tuncay Karaçay
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Dynamics of a rotor supported by air bearings is strongly depends on the pressure distribution between the rotor and the bearing. In this study, internal pressure in air bearings is numerical and experimental analyzed for different radial clearances. Firstly the pressure distribution between rotor and bearing is modeled using Reynold's equation and this model is solved numerically. The rotor-bearing system is also modeled in four degree of freedom and it is simulated for different radial clearances. Then, in order to validate numerical results, a test rig is designed and the rotor bearing system is run under the same operational conditions. Pressure signals of left and right bearings are recorded. Internal pressure variations are compared for numerical and experimental results for different radial clearances.Keywords: Air bearing, internal pressure, Reynold’s equation, rotor.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21381137 Dimensional Variations of Cement Matrices in the Presence of Metal Fibers
Authors: Fatima Setti, Ezziane Karim, Setti Bakhti, Negadi Kheira
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The objective of this study is to present and to analyze the feasibility of using steel fibers as reinforcement in the cementations matrix to minimize the effect of free shrinkage which is a major cause of cracks that have can observe on concrete structures, also to improve the mechanical resistances of this concrete reinforced. The experimental study was performed on specimens with geometric characteristics adapted to the testing. The tests of shrinkage apply on prismatic specimens, equipped with rods fixed to the ends with different dosages of fibers, it should be noted that the fibers used are hooked end of 50mm length and 67 slenderness. The results show that the compressive strength and flexural strength increases as the degree of incorporation of fibbers increases. And the shrinkage deformations are generally less important for fibers-reinforced concrete to those appearing in the concrete without fibers.
Keywords: Concrete, Steel fibers, Compression, Flexural, Deformation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16901136 The Rise of Nationalism among South Korean Youth and Democracy: An Analysis
Authors: Noor Sulastry Yurni Ahmad , Ki-Soo Eun
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The 2008 Candlelight Protests of Korea was very significant to portray the political environment among the South Korean youth. Many challenges and new advanced technologies have driven the youth community to be engaged in the political arena that has shifted them from traditional Korean youth to a very greater community. Due to historical perspective with the people of North Korea, the young generation has embraced different view of ethnic nationalism. This study examines the youth involvement in politics in line with their level of acceptance the practice of democracy. The increase usage of new media has shown great results in the survey results whereby the youth used as a platform to gain political information and brought higher degree of their sociopolitical interests among them. Furthermore, the rise of nationalism and patriotism will be discussed in this paper to the dynamism of the political approaches used by the Korea governmentKeywords: Nationalism, new media, political participation, youth
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 32071135 Cubic B-spline Collocation Method for Numerical Solution of the Benjamin-Bona-Mahony-Burgers Equation
Authors: M. Zarebnia, R. Parvaz
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In this paper, numerical solutions of the nonlinear Benjamin-Bona-Mahony-Burgers (BBMB) equation are obtained by a method based on collocation of cubic B-splines. Applying the Von-Neumann stability analysis, the proposed method is shown to be unconditionally stable. The method is applied on some test examples, and the numerical results have been compared with the exact solutions. The L∞ and L2 in the solutions show the efficiency of the method computationally.
Keywords: Benjamin-Bona-Mahony-Burgers equation, Cubic Bspline, Collocation method, Finite difference.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 36921134 Identifying Critical Success Factors for Data Quality Management through a Delphi Study
Authors: Maria Paula Santos, Ana Lucas
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Organizations support their operations and decision making on the data they have at their disposal, so the quality of these data is remarkably important and Data Quality (DQ) is currently a relevant issue, the literature being unanimous in pointing out that poor DQ can result in large costs for organizations. The literature review identified and described 24 Critical Success Factors (CSF) for Data Quality Management (DQM) that were presented to a panel of experts, who ordered them according to their degree of importance, using the Delphi method with the Q-sort technique, based on an online questionnaire. The study shows that the five most important CSF for DQM are: definition of appropriate policies and standards, control of inputs, definition of a strategic plan for DQ, organizational culture focused on quality of the data and obtaining top management commitment and support.
Keywords: Critical success factors, data quality, data quality management, Delphi, Q-Sort.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 11091133 The Role of Parents in Teaching Entrepreneurship Culture to Their Children in Family Businesses
Authors: Ahmet Diken, Meral Erdirençelebi
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Similar to economies in many countries; family-owned enterprises have a significant role in the development of Turkish economy. Although they have a large share in economic terms, their lifetime is limited to working life of their founders. Failure in achieving their sustainability deeply affects not only these businesses but also the economy. Therefore, two basic elements of family owned enterprises, family and organizational culture and especially entrepreneurship culture, should be examined closely. The degree of effectiveness of parents in instilling their children with entrepreneurship culture and their effects on children's profession choices are examined through face-to-face surveys with the managers owning family businesses randomly chosen among family-owned enterprises registered in Konya Chamber of Industry, which are active in specific sectors and which had different generations in their management.Keywords: Family-owned enterprises, entrepreneurship, entrepreneurship culture.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 12901132 A New Condition for Conflicting Bifuzzy Sets Based On Intuitionistic Evaluation
Authors: Imran C.T., Syibrah M.N., Mohd Lazim A.
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Fuzzy sets theory affirmed that the linguistic value for every contraries relation is complementary. It was stressed in the intuitionistic fuzzy sets (IFS) that the conditions for contraries relations, which are the fuzzy values, cannot be greater than one. However, complementary in two contradict phenomena are not always true. This paper proposes a new idea condition for conflicting bifuzzy sets by relaxing the condition of intuitionistic fuzzy sets. Here, we will critically forward examples using triangular fuzzy number in formulating a new condition for conflicting bifuzzy sets (CBFS). Evaluation of positive and negative in conflicting phenomena were calculated concurrently by relaxing the condition in IFS. The hypothetical illustration showed the applicability of the new condition in CBFS for solving non-complement contraries intuitionistic evaluation. This approach can be applied to any decision making where conflicting is very much exist.Keywords: Conflicting bifuzzy set, conflicting degree, fuzzy sets, fuzzy numbers.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16801131 An Expectation of the Rate of Inflation According to Inflation-Unemployment Interaction in Croatia
Authors: Zdravka Aljinović, Snježana Pivac, Boško Šego
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According to the interaction of inflation and unemployment, expectation of the rate of inflation in Croatia is estimated. The interaction between inflation and unemployment is shown by model based on three first-order differential i.e. difference equations: Phillips relation, adaptive expectations equation and monetary-policy equation. The resulting equation is second order differential i.e. difference equation which describes the time path of inflation. The data of the rate of inflation and the rate of unemployment are used for parameters estimation. On the basis of the estimated time paths, the stability and convergence analysis is done for the rate of inflation.Keywords: Differencing, inflation, time path, unemployment.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16141130 Robust Control of a Dynamic Model of an F-16 Aircraft with Improved Damping through Linear Matrix Inequalities
Authors: J. P. P. Andrade, V. A. F. Campos
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This work presents an application of Linear Matrix Inequalities (LMI) for the robust control of an F-16 aircraft through an algorithm ensuring the damping factor to the closed loop system. The results show that the zero and gain settings are sufficient to ensure robust performance and stability with respect to various operating points. The technique used is the pole placement, which aims to put the system in closed loop poles in a specific region of the complex plane. Test results using a dynamic model of the F-16 aircraft are presented and discussed.Keywords: F-16 Aircraft, linear matrix inequalities, pole placement, robust control.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16311129 Motion Planning and Control of Autonomous Robots in a Two-dimensional Plane
Authors: Avinesh Prasad, Bibhya Sharma, Jito Vanualailai
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This paper proposes a solution to the motion planning and control problem of a point-mass robot which is required to move safely to a designated target in a priori known workspace cluttered with fixed elliptical obstacles of arbitrary position and sizes. A tailored and unique algorithm for target convergence and obstacle avoidance is proposed that will work for any number of fixed obstacles. The control laws proposed in this paper also ensures that the equilibrium point of the given system is asymptotically stable. Computer simulations with the proposed technique and applications to a planar (RP) manipulator will be presented.Keywords: Point-mass Robot, Asymptotic stability, Motionplanning, Planar Robot Arm.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 16691128 A Quantitative Assessment of the Social Marginalization in Romania
Authors: Andra Costache, Rădiţa Alexe
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The analysis of the spatial disparities of social marginalization is a requirement in the present-day socio-economic and political context of Romania, an East-European state, member of the European Union since 2007, at present faced with the imperatives of the growth of its territorial cohesion. The main objective of this article is to develop a methodology for the assessment of social marginalization, in order to understand the intensity of the marginalization phenomenon at different spatial scales. The article proposes a social marginalization index (SMI), calculated through the integration of ten indicators relevant for the two components of social marginalization: the material component and the symbolical component. The results highlighted a strong connection between the total degree of social marginalization and the dependence on social benefits, unemployment rate, non-inclusion in the compulsory education, criminality rate, and the type of pension insurance.
Keywords: Romania, social marginalization index, territorial disparities.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 19611127 LQR Based PID Controller Design for 3-DOF Helicopter System
Authors: Santosh Kr. Choudhary
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In this article, LQR based PID controller design for 3DOF helicopter system is investigated. The 3-DOF helicopter system is a benchmark laboratory model having strongly nonlinear characteristics and unstable dynamics which make the control of such system a challenging task. This article first presents the mathematical model of the 3DOF helicopter system and then illustrates the basic idea and technical formulation for controller design. The paper explains the simple approach for the approximation of PID design parameters from the LQR controller gain matrix. The simulation results show that the investigated controller has both static and dynamic performance, therefore the stability and the quick control effect can be obtained simultaneously for the 3DOF helicopter system.
Keywords: 3DOF helicopter system, PID controller, LQR controller, modeling, simulation.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 52281126 Approximate Tension Buckling Capacity of Thin Edge-Cracked Web Plate Subjected to Pure Bending
Authors: Sebastian B. Mendes
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The presence of a vertical edge-crack within a web plate subjected to pure bending induces local compressive stresses about the crack which may cause tension buckling. Approximate theoretical expressions were derived for the critical far-field tensile stress and bending moment capacity of an edge-cracked web plate associated with tension buckling. These expressions were validated with finite element analyses and used to investigate the possibility of tension buckling in web-cracked trial girders. It was found that tension buckling is an unlikely occurrence unless the web is relatively thin or the crack is very long.Keywords: Fatigue crack, tension buckling, Rayleigh-Ritz, structural stability.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 20141125 Characterization of Inertial Confinement Fusion Targets Based on Transmission Holographic Mach-Zehnder Interferometer
Authors: B. Zare-Farsani, M. Valieghbal, M. Tarkashvand, A. H. Farahbod
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To provide the conditions for nuclear fusion by high energy and powerful laser beams, it is required to have a high degree of symmetry and surface uniformity of the spherical capsules to reduce the Rayleigh-Taylor hydrodynamic instabilities. In this paper, we have used the digital microscopic holography based on Mach-Zehnder interferometer to study the quality of targets for inertial fusion. The interferometric pattern of the target has been registered by a CCD camera and analyzed by Holovision software. The uniformity of the surface and shell thickness are investigated and measured in reconstructed image. We measured shell thickness in different zone where obtained non uniformity 22.82 percent.Keywords: Inertial confinement fusion, Mach-Zehnder interferometer, Digital holographic microscopy.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 13141124 Numerical Studies of Galerkin-type Time-discretizations Applied to Transient Convection-diffusion-reaction Equations
Authors: Naveed Ahmed, Gunar Matthies
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We deal with the numerical solution of time-dependent convection-diffusion-reaction equations. We combine the local projection stabilization method for the space discretization with two different time discretization schemes: the continuous Galerkin-Petrov (cGP) method and the discontinuous Galerkin (dG) method of polynomial of degree k. We establish the optimal error estimates and present numerical results which shows that the cGP(k) and dG(k)- methods are accurate of order k +1, respectively, in the whole time interval. Moreover, the cGP(k)-method is superconvergent of order 2k and dG(k)-method is of order 2k +1 at the discrete time points. Furthermore, the dependence of the results on the choice of the stabilization parameter are discussed and compared.
Keywords: Convection-diffusion-reaction equations, stabilized finite elements, discontinuous Galerkin, continuous Galerkin-Petrov.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1750