Abstract: This paper presents an efficient approach to feeder
reconfiguration for power loss reduction and voltage profile
imprvement in unbalanced radial distribution systems (URDS). In
this paper Genetic Algorithm (GA) is used to obtain solution for
reconfiguration of radial distribution systems to minimize the losses.
A forward and backward algorithm is used to calculate load flows in
unbalanced distribution systems. By simulating the survival of the
fittest among the strings, the optimum string is searched by
randomized information exchange between strings by performing
crossover and mutation. Results have shown that proposed algorithm
has advantages over previous algorithms The proposed method is
effectively tested on 19 node and 25 node unbalanced radial
distribution systems.
Abstract: One of the factors to maintain system survivability is
the adequate reactive power support to the system. Lack of reactive
power support may cause undesirable voltage decay leading to total
system instability. Thus, appropriate reactive power support scheme
should be arranged in order to maintain system stability. The strength
of a system capacity is normally denoted as system loadability. This
paper presents the enhancement of system loadability through
optimal reactive power planning technique using a newly developed
optimization technique, termed as Multiagent Immune Evolutionary
Programming (MAIEP). The concept of MAIEP is developed based
on the combination of Multiagent System (MAS), Artificial Immune
System (AIS) and Evolutionary Programming (EP). In realizing the
effectiveness of the proposed technique, validation is conducted on
the IEEE-26-Bus Reliability Test System. The results obtained from
pre-optimization and post-optimization process were compared
which eventually revealed the merit of MAIEP.
Abstract: The refueling of a transparent rectangular fuel tank
fitted with a standard filler pipe and roll-over valve was
experimentally studied. A fuel-conditioning cart, capable of
handling fuels of different Reid vapor pressure at a constant
temperature, was used to dispense fuel at the desired rate. The
experimental protocol included transient recording of the tank and
filler tube pressures while video recording the flow patterns in the
filler tube and tank during the refueling process. This information
was used to determine the effect of changes in the vent tube
diameter, fuel-dispense flow rate and fuel Reid vapor pressure on the
pressure-time characteristics and the occurrence of premature fuel
filling shut-off and fuel spill-back. Pressure-time curves for the case
of normal shut-off demonstrated the classic, three-phase
characteristic noted in the literature. The variation of the maximum
values of tank dome and filler tube pressures are analyzed in relation
to the occurrence of premature shut-off.
Abstract: The research on two-wheels balancing robot has
gained momentum due to their functionality and reliability when
completing certain tasks. This paper presents investigations into the
performance comparison of Linear Quadratic Regulator (LQR) and
PID-PID controllers for a highly nonlinear 2–wheels balancing robot.
The mathematical model of 2-wheels balancing robot that is highly
nonlinear is derived. The final model is then represented in statespace
form and the system suffers from mismatched condition. Two
system responses namely the robot position and robot angular
position are obtained. The performances of the LQR and PID-PID
controllers are examined in terms of input tracking and disturbances
rejection capability. Simulation results of the responses of the
nonlinear 2–wheels balancing robot are presented in time domain. A
comparative assessment of both control schemes to the system
performance is presented and discussed.
Abstract: In this study the enthalpies of dissociation for pure
methane and pure carbon dioxide was calculated using a hydrate
equilibrium data obtained in this study. The enthalpy of dissociation
was determined using Clausius-Clapeyron equation. The results were
compared with the values reported in literature obtained using
various techniques.
Abstract: Series of experimental tests were conducted on a
section of a 660 kW wind turbine blade to measure the pressure
distribution of this model oscillating in plunging motion. In order to
minimize the amount of data required to predict aerodynamic loads
of the airfoil, a General Regression Neural Network, GRNN, was
trained using the measured experimental data. The network once
proved to be accurate enough, was used to predict the flow behavior
of the airfoil for the desired conditions.
Results showed that with using a few of the acquired data, the
trained neural network was able to predict accurate results with
minimal errors when compared with the corresponding measured
values. Therefore with employing this trained network the
aerodynamic coefficients of the plunging airfoil, are predicted
accurately at different oscillation frequencies, amplitudes, and angles
of attack; hence reducing the cost of tests while achieving acceptable
accuracy.
Abstract: In this paper, we propose a dynamic TDMA slot
reservation (DTSR) protocol for cognitive radio ad hoc networks.
Quality of Service (QoS) guarantee plays a critically important role
in such networks. We consider the problem of providing QoS
guarantee to users as well as to maintain the most efficient use of
scarce bandwidth resources. According to one hop neighboring
information and the bandwidth requirement, our proposed protocol
dynamically changes the frame length and the transmission schedule.
A dynamic frame length expansion and shrinking scheme that
controls the excessive increase of unassigned slots has been
proposed. This method efficiently utilizes the channel bandwidth by
assigning unused slots to new neighboring nodes and increasing the
frame length when the number of slots in the frame is insufficient to
support the neighboring nodes. It also shrinks the frame length when
half of the slots in the frame of a node are empty. An efficient slot
reservation protocol not only guarantees successful data
transmissions without collisions but also enhance channel spatial
reuse to maximize the system throughput. Our proposed scheme,
which provides both QoS guarantee and efficient resource utilization,
be employed to optimize the channel spatial reuse and maximize the
system throughput. Extensive simulation results show that the
proposed mechanism achieves desirable performance in multichannel
multi-rate cognitive radio ad hoc networks.
Abstract: The link between Gröbner basis and linear algebra was
described by Lazard [4,5] where he realized the Gr¨obner basis
computation could be archived by applying Gaussian elimination over
Macaulay-s matrix .
In this paper, we indicate how same technique may be used to
SAGBI- Gröbner basis computations in invariant rings.
Abstract: In this paper, a discrete-time SIR epidemic model with nonlinear incidence rate, time delays and impulses is investigated. Sufficient conditions for the existence and uniqueness of periodic solutions are obtained by using contraction theorem and inequality techniques. An example is employed to illustrate our results.
Abstract: Traditionally, Internet has provided best-effort service to every user regardless of its requirements. However, as Internet becomes universally available, users demand more bandwidth and applications require more and more resources, and interest has developed in having the Internet provide some degree of Quality of Service. Although QoS is an important issue, the question of how it will be brought into the Internet has not been solved yet. Researches, due to the rapid advances in technology are proposing new and more desirable capabilities for the next generation of IP infrastructures. But neither all applications demand the same amount of resources, nor all users are service providers. In this way, this paper is the first of a series of papers that presents an architecture as a first step to the optimization of QoS in the Internet environment as a solution to a SMSE's problem whose objective is to provide public service to internet with certain Quality of Service expectations. The service provides new business opportunities, but also presents new challenges. We have designed and implemented a scalable service framework that supports adaptive bandwidth based on user demands, and the billing based on usage and on QoS. The developed application has been evaluated and the results show that traffic limiting works at optimum and so it does exceeding bandwidth distribution. However, some considerations are done and currently research is under way in two basic areas: (i) development and testing new transfer protocols, and (ii) developing new strategies for traffic improvements based on service differentiation.
Abstract: An attempt has been made to investigate the
machinability of zirconia toughened alumina (ZTA) inserts while
turning AISI 4340 steel. The insert was prepared by powder
metallurgy process route and the machining experiments were
performed based on Response Surface Methodology (RSM) design
called Central Composite Design (CCD). The mathematical model of
flank wear, cutting force and surface roughness have been developed
using second order regression analysis. The adequacy of model has
been carried out based on Analysis of variance (ANOVA) techniques.
It can be concluded that cutting speed and feed rate are the two most
influential factor for flank wear and cutting force prediction. For
surface roughness determination, the cutting speed & depth of cut
both have significant contribution. Key parameters effect on each
response has also been presented in graphical contours for choosing
the operating parameter preciously. 83% desirability level has been
achieved using this optimized condition.
Abstract: One main drawback of intrusion detection system is the
inability of detecting new attacks which do not have known
signatures. In this paper we discuss an intrusion detection method
that proposes independent component analysis (ICA) based feature
selection heuristics and using rough fuzzy for clustering data. ICA is
to separate these independent components (ICs) from the monitored
variables. Rough set has to decrease the amount of data and get rid of
redundancy and Fuzzy methods allow objects to belong to several
clusters simultaneously, with different degrees of membership. Our
approach allows us to recognize not only known attacks but also to
detect activity that may be the result of a new, unknown attack. The
experimental results on Knowledge Discovery and Data Mining-
(KDDCup 1999) dataset.
Abstract: This paper presents a 2-D hydrodynamic model of the ablated plasma when irradiating a 50 μm Al solid target with a single pulsed ion beam. The Lagrange method is used to solve the moving fluid for the ablated plasma production and formation mechanism. In the calculations, a 10-ns-single-pulsed of ion beam with a total energy density of 120 J/cm2, is used. The results show that the ablated plasma was formed after 2 ns of ion beam irradiation and it started to expand right after 4-6 ns. In addition, the 2-D model give a better understanding of pulsed ion beam-solid target ablated plasma production and expansion process clearer.
Abstract: This paper presents a method for obtaining the
desired reference current for Voltage Source Converter (VSC) of the Shunt Active Power Filter (SAPF) using Synchronous Reference Frame Theory. The method relies on the performance of the Proportional-Integral (PI) controller for
obtaining the best control performance of the SAPF. To
improve the performance of the PI controller, the feedback
path to the integral term is introduced to compensate the
winding up phenomenon due to integrator. Using Reference
Frame Transformation, reference signals are transformed from
a - b - c stationery frame to 0 - d - q rotating frame.
Using the PI controller, the reference signals in the 0 - d - q rotating frame are controlled to get the desired reference signals for the Pulse Width Modulation. The synchronizer, the Phase Locked Loop (PLL) with PI filter is used for
synchronization, with much emphasis on minimizing delays. The system performance is examined with Shunt Active Power Filter simulation model.
Abstract: Enterprise Architecture (EA) is a framework for description, coordination and alignment of all activities across the organization in order to achieve strategic goals using ICT enablers. A number of EA-compatible frameworks have been developed. We, in this paper, mainly focus on Federal Enterprise Architecture Framework (FEAF) since its reference models are plentiful. Among these models we are interested here in its business reference model (BRM). The test process is one important subject of an EA project which is to somewhat overlooked. This lack of attention may cause drawbacks or even failure of an enterprise architecture project. To address this issue we intend to use International Software Testing Qualification Board (ISTQB) framework and standard test suites to present a method to improve EA testing process. The main challenge is how to communicate between the concepts of EA and ISTQB. In this paper, we propose a method for integrating these concepts.
Abstract: The paper describes ergonomics problems trend of
student at B5101 classroom building 2, Suranaree University of
Technology. The objective to survey ergonomics problems and effect
from use chairs for sitting in class room. The result from survey
method 100 student they use lecture chair for sitting in classroom
more than 2 hours/ day by RULA[1]. and Body discomfort survey[2].
The result from Body discomfort survey contribute fatigue problems
at neck, lower back, upper back and right shoulder 2.93, 2.91, 2.33,
1.75 respectively and result from RULA contribute fatigue problems
at neck, body and right upper arm 4.00, 3.75 and 3.00 respectively
are consistent. After that the researcher provide improvement plan
for design new chair support student fatigue reduction by prepare
data of sample anthropometry and design ergonomics chair prototype
3 unit. Then sample 100 student trial to use new chair and evaluate
again by RULA, Body discomfort and satisfaction. The result from
trial new chair after improvement by RULA present fatigue reduction
average of head and neck from 4.00 to 2.25 , body and trunk from
3.75 to 2.00 and arm force from 1.00 to 0.25 respectively. The result
from trial new chair after improvement by Body discomfort present
fatigue reduction average of lower back from 2.91 to 0.87, neck from
2.93 to 1.24, upper back 2.33 to 0.84 and right upper arm from 1.75
to 0.74. That statistical of RULA and Body discomfort survey
present fatigue reduction after improvement significance with a
confidence level of 95% (p-value 0.05). When analyzing the
relationship of fatigue as part of the body by Chi – square test during
RULA and Body discomfort that before and after improvements were
consistent with the significant level of confidence 95% (p-value 0.05)
. Moreover the students satisfaction result from trial with a new chair
for 30 minutes [3]. 72 percent very satisfied of the folding of the
secondary writing simple 66% the width of the writing plate, 64% the
suitability of the writing plate, 62% of soft seat cushion and 61%
easy to seat the chair.
Abstract: A new Feed-Forward/Feedback Generalized
Minimum Variance Pole-placement Controller to incorporate the
robustness of classical pole-placement into the flexibility of
generalized minimum variance self-tuning controller for Single-Input
Single-Output (SISO) has been proposed in this paper. The design,
which provides the user with an adaptive mechanism, which ensures
that the closed loop poles are, located at their pre-specified positions.
In addition, the controller design which has a feed-forward/feedback
structure overcomes the certain limitations existing in similar poleplacement
control designs whilst retaining the simplicity of
adaptation mechanisms used in other designs. It tracks set-point
changes with the desired speed of response, penalizes excessive
control action, and can be applied to non-minimum phase systems.
Besides, at steady state, the controller has the ability to regulate the
constant load disturbance to zero. Example simulation results using
both simulated and real plant models demonstrate the effectiveness of
the proposed controller.
Abstract: The purpose of the present work was to study the
production and process parameters optimization for the synthesis of
cellulase from Trichoderma viride in solid state fermentation (SSF)
using an agricultural wheat straw as substrates; as fungal conversion
of lignocellulosic biomass for cellulase production is one among the
major increasing demand for various biotechnological applications.
An optimization of process parameters is a necessary step to get
higher yield of product. Several kinetic parameters like pretreatment,
extraction solvent, substrate concentration, initial moisture content,
pH, incubation temperature and inoculum size were optimized for
enhanced production of third most demanded industrially important
cellulase. The maximum cellulase enzyme activity 398.10±2.43
μM/mL/min was achieved when proximally analyzed lignocellulosic
substrate wheat straw inocubated at 2% HCl as pretreatment tool
along with distilled water as extraction solvent, 3% substrate
concentration 40% moisture content with optimum pH 5.5 at 45°C
incubation temperature and 10% inoculum size.
Abstract: This paper To get the angle value with a MEMS rate
gyroscope in some specific field, the usual method is to make an
integral operation to the rate output, which will lead the error
cumulating effect. So the rate gyro is not suitable. MEMS rate
integrating gyroscope (MRIG) will solve this problem. A DSP system
has been developed to implement the control arithmetic. The system
can measure the angle of rotation directly by the control loops that
make the sensor work in whole-angle mode. Modeling the system with
MATLAB, desirable results of angle outputs are got, which prove the
feasibility of the control arithmetic.
Abstract: This work deals with problems of tool axis inclination angles in ball-end milling. Tool axis inclination angle contributes to improvement of functional surface properties (surface integrity - surface roughness, residual stress, micro hardness, etc.), decreasing cutting forces and improving production. By milling with ball-end milling tool, using standard way of cutting, when work piece and cutting tool contain right angle, we have zero cutting speed on edge. At this point cutting tool only pushes material into the work piece. Here we can observe the following undesirable effects - chip contraction, increasing of cutting temperature, increasing vibrations or creation of built-up edge. These effects have negative results – low quality of surface and decreasing of tool life (in the worse case even it is pinching out). These effects can be eliminated with the tilt of cutting tool or tilt of work piece.