Abstract: The Wind Turbine Modeling in Wind Energy Conversion System (WECS) using Doubly-Fed Induction Generator (DFIG) PI Controller based design is presented. To study about the variable wind speed. The PI controller performs responding to the dynamic performance. The objective is to study the characteristic of wind turbine and finding the optimum wind speed suitable for wind turbine performance. This system will allow the specification setting (2.5MW). The output active power also corresponding same the input is given. And the reactive power produced by the wind turbine is regulated at 0 Mvar. Variable wind speed is optimum for drive train performance at 12.5 m/s (at maximum power coefficient point) from the simulation of DFIG by Simulink is described.
Abstract: This paper presents a comparison between two Pulse
Width Modulation (PWM) algorithms applied to a three-level Neutral
Point Clamped (NPC) Voltage Source Inverter (VSI). The first
algorithm applied is the triangular-sinusoidal strategy; the second is
the Space Vector Pulse Width Modulation (SVPWM) strategy. In the
first part, we present a topology of three-level NCP VSI. After that,
we develop the two PWM strategies to control this converter. At the
end the experimental results are presented.
Abstract: Signature represents an individual characteristic of a
person which can be used for his / her validation. For such application
proper modeling is essential. Here we propose an offline signature
recognition and verification scheme which is based on extraction of
several features including one hybrid set from the input signature
and compare them with the already trained forms. Feature points
are classified using statistical parameters like mean and variance.
The scanned signature is normalized in slant using a very simple
algorithm with an intention to make the system robust which is
found to be very helpful. The slant correction is further aided by the
use of an Artificial Neural Network (ANN). The suggested scheme
discriminates between originals and forged signatures from simple
and random forgeries. The primary objective is to reduce the two
crucial parameters-False Acceptance Rate (FAR) and False Rejection
Rate (FRR) with lesser training time with an intension to make the
system dynamic using a cluster of ANNs forming a multiple classifier
system.
Abstract: Hidden failure in a protection system has been
recognized as one of the main reasons which may cause to a power
system instability leading to a system cascading collapse. This paper
presents a computationally systematic approach used to obtain the
estimated average probability of a system cascading collapse by
considering the effect of probability hidden failure in a protection
system. The estimated average probability of a system cascading
collapse is then used to determine the severe loading condition
contributing to the higher risk of critical system cascading collapse.
This information is essential to the system utility since it will assist
the operator to determine the highest point of increased system
loading condition prior to the event of critical system cascading
collapse.
Abstract: This paper challenges the relevance of knowledgebased
management research by arguing that the majority of the
literature emphasizes information and knowledge provision instead of
their business usage. For this reason the related processes are
considered valuable and eligible as such, which has led to
overlapping nature of knowledge-based management disciplines. As
a solution, this paper turns the focus on the information usage. Value
of knowledge and respective management tasks are then defined by
the business need and the knowledge-user becomes the main actor.
The paper analyses the prevailing literature streams and recognizes
the need for a more focused and robust understanding of knowledgebased
value creation. The paper contributes by synthetizing the
existing literature and pinpointing the essence of knowledge-based
management disciplines.
Abstract: Near-infrared (NIR) spectroscopy is a widely used
method for material identification for laboratory and industrial applications.
While standard spectrometers only allow measurements at
one sampling point at a time, NIR Spectral Imaging techniques can
measure, in real-time, both the size and shape of an object as well as
identify the material the object is made of. The online classification
and sorting of recovered paper with NIR Spectral Imaging (SI)
is used with success in the paper recycling industry throughout
Europe. Recently, the globalisation of the recycling material streams
caused that water-based flexographic-printed newspapers mainly from
UK and Italy appear also in central Europe. These flexo-printed
newspapers are not sufficiently de-inkable with the standard de-inking
process originally developed for offset-printed paper. This de-inking
process removes the ink from recovered paper and is the fundamental
processing step to produce high-quality paper from recovered paper.
Thus, the flexo-printed newspapers are a growing problem for the
recycling industry as they reduce the quality of the produced paper
if their amount exceeds a certain limit within the recovered paper
material.
This paper presents the results of a research project for the
development of an automated entry inspection system for recovered
paper that was jointly conducted by CTR AG (Austria) and PTS
Papiertechnische Stiftung (Germany). Within the project an NIR
SI prototype for the identification of flexo-printed newspaper has
been developed. The prototype can identify and sort out flexoprinted
newspapers in real-time and achieves a detection accuracy
for flexo-printed newspaper of over 95%. NIR SI, the technology the
prototype is based on, allows the development of inspection systems
for incoming goods in a paper production facility as well as industrial
sorting systems for recovered paper in the recycling industry in the
near future.
Abstract: Self-organizing map (SOM) is a well known data reduction technique used in data mining. Data visualization can reveal structure in data sets that is otherwise hard to detect from raw data alone. However, interpretation through visual inspection is prone to errors and can be very tedious. There are several techniques for the automatic detection of clusters of code vectors found by SOMs, but they generally do not take into account the distribution of code vectors; this may lead to unsatisfactory clustering and poor definition of cluster boundaries, particularly where the density of data points is low. In this paper, we propose the use of a generic particle swarm optimization (PSO) algorithm for finding cluster boundaries directly from the code vectors obtained from SOMs. The application of our method to unlabeled call data for a mobile phone operator demonstrates its feasibility. PSO algorithm utilizes U-matrix of SOMs to determine cluster boundaries; the results of this novel automatic method correspond well to boundary detection through visual inspection of code vectors and k-means algorithm.
Abstract: Game theory could be used to analyze the conflicted
issues in the field of information hiding. In this paper, 2-phase game
can be used to build the embedder-attacker system to analyze the
limits of hiding capacity of embedding algorithms: the embedder
minimizes the expected damage and the attacker maximizes it. In the
system, the embedder first consumes its resource to build embedded
units (EU) and insert the secret information into EU. Then the attacker
distributes its resource evenly to the attacked EU. The expected
equilibrium damage, which is maximum damage in value from the
point of view of the attacker and minimum from the embedder against
the attacker, is evaluated by the case when the attacker attacks a
subset from all the EU. Furthermore, the optimal equilibrium capacity
of hiding information is calculated through the optimal number of EU
with the embedded secret information. Finally, illustrative examples
of the optimal equilibrium capacity are presented.
Abstract: The optimization and control problem for 4D trajectories
is a subject rarely addressed in literature. In the 4D navigation
problem we define waypoints, for each mission, where the arrival
time is specified in each of them. One way to design trajectories for
achieving this kind of mission is to use the trajectory optimization
concepts. To solve a trajectory optimization problem we can use
the indirect or direct methods. The indirect methods are based on
maximum principle of Pontryagin, on the other hand, in the direct
methods it is necessary to transform into a nonlinear programming
problem. We propose an approach based on direct methods with a
pseudospectral integration scheme built on Chebyshev polynomials.
Abstract: With the rapid advanced of technology, the industrial processes become increasingly demanding, from the point of view, power quality and controllability. The advent of multi levels inverters responds partially to these requirements. But actually, the new generation of multi-cells inverters permits to reach more performances, since, it offers more voltage levels. The disadvantage in the increase of voltage levels by the number of cells in cascades is on account of series igbts synchronisation loss, from where, a limitation of cells in cascade to 4. Regarding to these constraints, a new topology is proposed in this paper, which increases the voltage levels of the three-cell inverter from 4 to 8; with the same number of igbts, and using less stored energy in the flaying capacitors. The details of operation and modelling of this new inverter structure are also presented, then tested thanks to a three phase induction motor. KeywordsFlaying capacitors, Multi-cells inverter, pwm, switchers, modelling.
Abstract: Access Management is the proactive management of
vehicular access points to land parcels adjacent to all manner of
roadways. Good access management promotes safe and efficient use
of the transportation network. This study attempts to utilize archived
data from the University Technology of Malaysia on-campus area to
assess the accuracy with which access management display some
benefits. Results show that usage of access management reduces
delay and fewer crashes. Clustered development can improve
walking, cycling and transit travel, reduce parking requirements and
improve emergency responses. Effective Access Management
planning can also reduce total roadway facility costs by reducing the
number of driveways and intersections. At the end after presenting
recommendations some of the travel impact, and benefits that
can be derived if these suggestions are implemented have
been summarized with the related comments.
Abstract: The present article deals with a composite casting process that allows to produce bilayer AlSn6-Al strips based on the technique of horizontal continuous casting. In the first part experimental investigations on the production of a single layer AlSn6 strip are described. Afterwards essential results of basic compound casting trials using simple test specimen are presented to define the thermal conditions required for a metallurgical compound between the alloy AlSn6 and pure aluminium. Subsequently, numerical analyses are described. A finite element model was used to examine a continuous composite casting process. As a result of the simulations the main influencing parameters concerning the thermal conditions within the composite casting region could be pointed out. Finally, basic guidance is given for the design of an appropriate composite mould system.
Abstract: In this paper, an alternating implicit block method for
solving two dimensional scalar wave equation is presented. The
new method consist of two stages for each time step implemented
in alternating directions which are very simple in computation. To
increase the speed of computation, a group of adjacent points is
computed simultaneously. It is shown that the presented method
increase the maximum time step size and more accurate than the
conventional finite difference time domain (FDTD) method and other
existing method of natural ordering.
Abstract: Active power filter continues to be a powerful tool to control harmonics in power systems thereby enhancing the power quality. This paper presents a fuzzy tuned PID controller based shunt active filter to diminish the harmonics caused by non linear loads like thyristor bridge rectifiers and imbalanced loads. Here Fuzzy controller provides the tuning of PID, based on firing of thyristor bridge rectifiers and variations in input rms current. The shunt APF system is implemented with three phase current controlled Voltage Source Inverter (VSI) and is connected at the point of common coupling for compensating the current harmonics by injecting equal but opposite filter currents. These controllers are capable of controlling dc-side capacitor voltage and estimating reference currents. Hysteresis Current Controller (HCC) is used to generate switching signals for the voltage source inverter. Simulation studies are carried out with non linear loads like thyristor bridge rectifier along with unbalanced loads and the results proved that the APF along with fuzzy tuned PID controller work flawlessly for different firing angles of non linear load.
Abstract: detecting the deadlock is one of the important
problems in distributed systems and different solutions have been
proposed for it. Among the many deadlock detection algorithms,
Edge-chasing has been the most widely used. In Edge-chasing
algorithm, a special message called probe is made and sent along
dependency edges. When the initiator of a probe receives the probe
back the existence of a deadlock is revealed. But these algorithms are
not problem-free. One of the problems associated with them is that
they cannot detect some deadlocks and they even identify false
deadlocks. A key point not mentioned in the literature is that when
the process is waiting to obtain the required resources and its
execution has been blocked, how it can actually respond to probe
messages in the system. Also the question of 'which process should
be victimized in order to achieve a better performance when multiple
cycles exist within one single process in the system' has received
little attention. In this paper, one of the basic concepts of the
operating system - daemon - will be used to solve the problems
mentioned. The proposed Algorithm becomes engaged in sending
probe messages to the mandatory daemons and collects enough
information to effectively identify and resolve multi-cycle deadlocks
in distributed systems.
Abstract: Due to the excess of a vehicle operation through its life, some elements may face failure and deteriorate with time. This leads us to carry out maintenance, repair, tune up or full overhaul. After a certain period, the vehicle elements deteriorations increase with time which causes a very high increase of doing the maintenance operations and their costs. However, the logic decision at this point is to replace the current vehicle by a new one with minimum failure and maximum income. The importance of studying vehicle replacement problems come from the increase of stopping days due to many deteriorations in the vehicle parts. These deteriorations increase year after year causing an increase of operating costs and decrease the vehicle income. Vehicle replacement aims to determine the optimum time to keep, maintain, overhaul, renew and replace vehicles. This leads to an improvement in vehicle income, total operating costs, maintenance cost, fuel and oil costs, ton-kilometers, vehicle and engine performance, vehicle noise, vibration, and pollution. The aim of this paper is to find the optimum replacement policies of Kuwait Passenger Transport Company (KPTCP) fleet of busses. The objective of these policies is to maximize the busses pure profits. The dynamic programming (D.P.) technique is used to generate the busses optimal replacement policies
Abstract: In this paper, linear multistep technique using power
series as the basis function is used to develop the block methods
which are suitable for generating direct solution of the special second
order ordinary differential equations with associated initial or
boundary conditions. The continuous hybrid formulations enable us
to differentiate and evaluate at some grids and off – grid points to
obtain two different four discrete schemes, each of order (5,5,5,5)T,
which were used in block form for parallel or sequential solutions of
the problems. The computational burden and computer time wastage
involved in the usual reduction of second order problem into system
of first order equations are avoided by this approach. Furthermore, a
stability analysis and efficiency of the block methods are tested on
linear and non-linear ordinary differential equations and the results
obtained compared favorably with the exact solution.
Abstract: Number of documents being created increases at an
increasing pace while most of them being in already known topics
and little of them introducing new concepts. This fact has started a
new era in information retrieval discipline where the requirements
have their own specialties. That is digging into topics and concepts
and finding out subtopics or relations between topics. Up to now IR
researches were interested in retrieving documents about a general
topic or clustering documents under generic subjects. However these
conventional approaches can-t go deep into content of documents
which makes it difficult for people to reach to right documents they
were searching. So we need new ways of mining document sets
where the critic point is to know much about the contents of the
documents. As a solution we are proposing to enhance LSI, one of
the proven IR techniques by supporting its vector space with n-gram
forms of words. Positive results we have obtained are shown in two
different application area of IR domain; querying a document
database, clustering documents in the document database.
Abstract: We intend to point out the differences which exist
between the classical Gini concentration coefficient and a proposed
bipolarization index defined for an arbitrary random variable which
have a finite support.
In fact Gini's index measures only the "poverty degree" for the
individuals from a given population taking into consideration their
wages. The Gini coefficient is not so sensitive to the significant
income variations in the "rich people class" .
In practice there are multiple interdependent relations between the
pauperization and the socio-economical polarization phenomena. The
presence of a strong pauperization aspect inside the population
induces often a polarization effect in this society. But the
pauperization and the polarization phenomena are not identical. For
this reason it isn't always adequate to use a Gini type coefficient,
based on the Lorenz order, to estimate the bipolarization level of the
individuals from the studied population.
The present paper emphasizes these ideas by considering two
families of random variables which have a linear or a triangular type
distributions. In addition, the continuous variation, depending on the
parameter "time" of the chosen distributions, could simulate a real
dynamical evolution of the population.
Abstract: The distillation process in the general sense is a
relatively simple technique from the standpoints of its principles.
When dedicating distillation to water treatment and specifically
producing fresh water from sea, ocean and/ briny waters it is
interesting to notice that distillation has no limitations or domains of
applicability regarding the nature or the type of the feedstock water.
This is not the case however for other techniques that are
technologically quite complex, necessitate bigger capital investments
and are limited in their usability. In a previous paper we have
explored some of the effects of temperature on yield. In this paper,
we continue building onto that knowledge base and focus on the
effects of several additional engineering and design variables on
productivity.