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Search Results: 1 - 10 of 496 matches for " tuning "
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Development and Experimental Measurements of a Tunable Antenna  [PDF]
Vasilis Raptis, Giorgos Tatsis, Spyridon K. Chronopoulos, Stavros Mallios, Panos Kostarakis
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53026

Modern telecommunication systems need to be equipped with antennas that are precisely tuned to more than one frequency in order to allow operation in several bands. Antenna precise tuning to the desired frequency is very important for system performance. In this paper the operating frequency of a PIFA antenna is adjusted using a varactor. This configuration has the advantage of continuous tuning, thus correcting any frequency deviation due to environmental or other changes. The PIFA antenna’s tuning ranges from 860 MHz to 1025 MHz. Also, the geometry of the antenna is studied through simulations and the effect of the varactor is tested experimentally.

Jorge Abud Sebastiani,Anna Bandini Bandiello,Luis Eduardo Araya Ramos
Didasc@lia : Didáctica y Educación , 2012,
Abstract: Tuning Latin America is a partnership that seeks and builds language and systems, transitional and trans. In the framework of the ALFA Tuning Latin America was a group of area geology (2006), with representatives from universities in the countries of Latin America. The overall objective is to apply the generic and specific skills in that area. It is designed as a space for reflection of actors committed to professional education, that through consensus-building, progress in the development of easily comparable and understandable in a cohesive way throughout Latin America. The idea of bringing forward a proposal as the Tuning Latin America, appeared in Europe but raised in America. The methodology used was based on consultations on specific behaviors noticing similarities in the processes of academic training in all Latin American countries that participated, applying a descriptive statistical method, considering the calculation of the mean and standard deviation of the variable obtained surveys. We analyzed and discussed the outlook of the subject area in different countries, we analyzed the generic skills developed earlier in the project, identified the specific skills and methods of consultation for evaluation. The results highlights the importance of obtaining a broad spectrum of both countries and institutions to consolidate the project.
Tuning the climate of a global model
Thorsten Mauritsen, Bjorn Stevens, Erich Roeckner, Traute Crueger, Monika Esch, Marco Giorgetta, Helmuth Haak, Johann Jungclaus, Daniel Klocke, Daniela Matei, Uwe Mikolajewicz, and Robert Pincus,Hauke Schmidt, and Lorenzo Tomassini
Journal of Advances in Modeling Earth Systems , 2012,
Abstract: During a development stage global climate models have their properties adjusted or tuned in various ways to best match the known state of the Earth's climate system. These desired properties are observables, such as the radiation balance at the top of the atmosphere, the global mean temperature, sea ice, clouds and wind fields. The tuning is typically performed by adjusting uncertain, or even non-observable, parameters related to processes not explicitly represented at the model grid resolution. The practice of climate model tuning has seen an increasing level of attention because key model properties, such as climate sensitivity, have been shown to depend on frequently used tuning parameters. Here we provide insights into how climate model tuning is practically done in the case of closing the radiation balance and adjusting the global mean temperature for the Max Planck Institute Earth System Model (MPI-ESM). We demonstrate that considerable ambiguity exists in the choice of parameters, and present and compare three alternatively tuned, yet plausible configurations of the climate model. The impacts of parameter tuning on climate sensitivity was less than anticipated.
Self-Sensing and –Actuating Probes for Tapping Mode AFM Measurements of Soft Polymers at a Wide Range of Temperatures  [PDF]
Nadejda B. Matsko, Julian Wagner, Anton Efimov, Ines Haynl, Stefan Mitsche, Wolfgang Czapek, Boris Matsko, Werner Grogger, Ferdinand Hofer
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.22012
Abstract: Self-sensing and –actuating probes optimized for conventional tapping mode atomic force microscopy (AFM) are described. 32-kHz quartz tuning forks with a chemically etched and focus ion beam (FIB) sharpened (curvature radii are 5-10 nm) tungsten tip are stable at air and liquid nitrogen atmosphere and at a wide range of temperatures. If driven at constant frequency, the scan speed of such sensors can be up to 3 Hz. AFM was performed on polymer samples in order to study the stability and applicability of these sensor for investigation of soft materials with high dynamical tendencies.
Sliding Mode Control with Auto-Tuning Law for Maglev System  [PDF]
L.L. Zhang, Z.Z. Zhang, Z.Q. Long, A.M. Hao
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.22015
Abstract: This paper presents a control strategy for maglev system based on the sliding mode controller with auto-tuning law. The designed adaptive controller will replace the conventional sliding mode control (SMC) to eliminate the chattering resulting from the SMC. The stability of maglev system is ensured based on the Lyapunov theory. Simulation results verify the effectiveness of the proposed method. In addition, the advantages of the proposed controller are indicated in comparison with a traditional sliding mode controller.
Does Aristotle Refute the Harmonia Theory of the Soul?  [PDF]
Douglas J. Young
Open Journal of Philosophy (OJPP) , 2013, DOI: 10.4236/ojpp.2013.31008

In Aristotle’s On the Soul he considers and refutes two versions of the harmonia theory of the soul’s relation to the body. According to the harmonia theory, the soul is to the body what the tuning of a musical instrument is to its material parts. Though he believes himself to have entirely dismissed the view, he has not. I argue that Aristotle’s hylomorphic account is, in fact, an instance of the harmonia theory.

An Approach to Developing a Performance Test Based on the Tradeoffs from SW Architectures  [PDF]
Byoungju Choi, Miso Yoon, Heejin Kim
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.64024

In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.

Simplified Optimization Routine for Tuning Robust Fractional Order Controllers  [PDF]
Cristina I. Muresan
American Journal of Computational Mathematics (AJCM) , 2013, DOI: 10.4236/ajcm.2013.33B002

Fractional order controllers have been used intensively over the last decades in controlling different types of processes. The main methods for tuning such controllers are based on a frequency domain approach followed by optimization routine, generally in the form of the Matlab fminsearch, but also evolving to more complex routines, such as the genetic algorithms. An alternative to these time consuming optimization routines, a simple graphical method has been proposed. However, these graphical methods are not suitable for all combinations of the imposed performance specifications. To preserve their simplicity, but also to make these graphical methods generally applicable, a modified graphical method using a very straightforward and simple optimization routine is proposed within the paper. Two case studies are presented, for tuning fractional order PI and PD controllers.

Linear Programming for Optimum PID Controller Tuning  [PDF]
Edimar J. Oliveira, Leonardo M. Honorio, Alexandre H. Anzai, Tamara X. Soares
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.56084

This work presents a new methodology based on Linear Programming (LP) to tune Proportional-Integral-Derivative (PID) control parameters. From a specification of a desired output time domain of the plant, a linear optimization system is proposed to adjust the PID controller leading the output signal to stable operation condition with minimum oscillations. The constraint set used in the optimization process is defined by using numerical integration approach. The generated optimization problem is convex and easily solved using an interior point algorithm. Results obtained using familiar plants from literature have shown that the proposed linear programming problem is very effective for tuning PID controllers.

Automated Performance Tuning of Data Management Systems with Materializations and Indices  [PDF]
Nan N. Noon, Janusz R. Getta
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.45007

Automated performance tuning of data management systems offer various benefits such as improved performance, declined administration costs, and reduced workloads to database administrators (DBAs). Currently, DBAs tune the performance of database systems with a little help from the database servers. In this paper, we propose a new technique for automated performance tuning of data management systems. Firstly, we show how to use the periods of low workload time for performance improvements in the periods of high workload time. We demonstrate that extensions of a database system with materialised views and indices when a workload is low may contribute to better performance for a successive period of high workload. The paper proposes several online algorithms for continuous processing of estimated database workloads and for the discovery of the best plan for materialised view and index database extensions and of elimination of the extensions that are no longer needed. We present the results of experiments that show how the proposed automated performance tuning technique improves the overall performance of a data management system.

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