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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.
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.
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.
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
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.
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.