Abstract: The performance of sensor-less controlled induction
motor drive depends on the accuracy of the estimated speed.
Conventional estimation techniques being mathematically complex
require more execution time resulting in poor dynamic response. The
nonlinear mapping capability and powerful learning algorithms of
neural network provides a promising alternative for on-line speed
estimation. The on-line speed estimator requires the NN model to be
accurate, simpler in design, structurally compact and computationally
less complex to ensure faster execution and effective control in real
time implementation. This in turn to a large extent depends on the
type of Neural Architecture. This paper investigates three types of
neural architectures for on-line speed estimation and their
performance is compared in terms of accuracy, structural
compactness, computational complexity and execution time. The
suitable neural architecture for on-line speed estimation is identified
and the promising results obtained are presented.
Abstract: This paper presents a mean for reducing the torque
variation during the revolution of a vertical-axis wind turbine
(VAWT) by increasing the blade number. For this purpose, twodimensional
CDF analysis have been performed on a straight-bladed
Darreius-type rotor. After describing the computational model, a
complete campaign of simulations based on full RANS unsteady
calculations is proposed for a three, four and five-bladed rotor
architecture characterized by a NACA 0025 airfoil. For each
proposed rotor configuration, flow field characteristics are
investigated at several values of tip speed ratio, allowing a
quantification of the influence of blade number on flow geometric
features and dynamic quantities, such as rotor torque and power.
Finally, torque and power curves are compared for the analyzed
architectures, achieving a quantification of the effect of blade number
on overall rotor performance.
Abstract: Performance of vehicle depends on driving patterns
and vehicle drive train configuration. Driving patterns depends on
traffic condition, road condition and driver behavior. HEV design is
carried out under certain constrain like vehicle operating range,
acceleration, decelerations, maximum speed and road grades which
are directly related to the driving patterns. Therefore the detailed
study on HEV performance over a different drive cycle is required
for selection and sizing of HEV components. A simple hardware is
design to measured velocity v/s time profile of the vehicle by
operating vehicle on Indian roads under real traffic conditions. To
size the HEV components, a detailed dynamic model of the vehicle is
developed considering the effect of inertia of rotating components
like wheels, drive chain, engine and electric motor. Using vehicle
model and different Indian drive cycles data, total tractive power
demanded by vehicle and power supplied by individual components
has been calculated.Using above information selection and estimation
of component sizing for HEV is carried out so that HEV performs
efficiently under hostile driving condition. Complete analysis is
carried out in LABVIEW.
Abstract: The demand for autonomous resource
management for distributed systems has increased in recent
years. Distributed systems require an efficient and powerful
communication mechanism between applications running on
different hosts and networks. The use of mobile agent
technology to distribute and delegate management tasks
promises to overcome the scalability and flexibility limitations
of the currently used centralized management approach. This
work proposes a multiagent system that adopts mobile agents
as a technology for tasks distribution, results collection, and
management of resources in large-scale distributed systems. A
new mobile agent-based approach for collecting results from
distributed system elements is presented. The technique of
artificial intelligence based on intelligent agents giving the
system a proactive behavior. The presented results are based
on a design example of an application operating in a mobile
environment.
Abstract: In this paper, we propose an easily computable proximity index for predicting voltage collapse of a load bus using only measured values of the bus voltage and power; Using these measurements a polynomial of fourth order is obtained by using LES estimation algorithms. The sum of the absolute values of the polynomial coefficient gives an idea of the critical bus. We demonstrate the applicability of our proposed method on 6 bus test system. The results obtained verify its applicability, as well as its accuracy and the simplicity. From this indicator, it is allowed to predict the voltage instability or the proximity of a collapse. Results obtained by the PV curve are compared with corresponding values by QV curves and are observed to be in close agreement.
Abstract: Active vibration isolation systems are less commonly
used than passive systems due to their associated cost and power
requirements. In principle, semi-active isolation systems can deliver
the versatility, adaptability and higher performance of fully active
systems for a fraction of the power consumption. Various semi-active
control algorithms have been suggested in the past. This paper
studies the 4DOF model of semi-active suspension performance
controlled by on–off and continuous skyhook damping control
strategy. The frequency and transient responses of model are
evaluated in terms of body acceleration, roll angle and tire deflection
and are compared with that of a passive damper. The results show
that the semi-active system controlled by skyhook strategy always
provides better isolation than a conventional passively damped
system except at tire natural frequencies.
Abstract: In order to study the influence of different methods of controlling weeds such as mechanical weeding and mechanical weeder efficiency analysis in mechanical cultivation conditions, in farming year of 2011 an experiment was done in a farm in coupling and development of technology center in Haraz,Iran. The treatments consisted of (I) control treatment: where no weeding was done, (II) use of mechanical weeding without engine and (III) power mechanical weeding. Results showed that experimental treatments had significantly different effects (p=0.05) on yield traits and number of filled grains per panicle, while treatments had the significant effects on grain weight and dry weight of weeds in the first, second and third weeding methods at 1% of confidence level. Treatment (II) had its most significant effect on number of filled grains per panicle and yield performance standpoint, which was 3705.97 kg ha-1 in its highest peak. Treatment (III) was ranked as second influential with 3559.8 kg ha-1. In addition, under (I) treatments, 2364.73 kg ha-1 of yield produced. The minimum dry weights of weeds in all weeding methods were related to the treatment (II), (III) and (I), respectively. The correlation coefficient analysis showed that total yield had a significant positive correlation with the panicle grain yield per plant (r= 0.55*) and the number of grains per panicle-1 (r= 0.57*) and the number of filled grains (r= 0.63*). Total rice yield also had negative correlation of r= -0. 64* with weed dry weight at second weed sampling time (17 DAT). The weed dry weight at third and fourth sampling times (24 and 40 DAT) had negative correlations of -0.65** and r=-0.61* with rice yield, respectively.
Abstract: In this paper, Exp-function method is used for some exact solitary solutions of the generalized Pochhammer-Chree equation. It has been shown that the Exp-function method, with the help of symbolic computation, provides a very effective and powerful mathematical tool for solving nonlinear partial differential equations. As a result, some exact solitary solutions are obtained. It is shown that the Exp-function method is direct, effective, succinct and can be used for many other nonlinear partial differential equations.
Abstract: power-line networks are promise infrastructure for
broadband services provision to end users. However, the network
performance is affected by stochastic channel changing which is due
to load impedances, number of branches and branched line lengths. It
has been proposed that multi-carrier modulations techniques such as
orthogonal frequency division multiplexing (OFDM), Multi-Carrier
Spread Spectrum (MC-SS), wavelet OFDM can be used in such
environment. This paper investigates the performance of different
indoor topologies of power-line networks that uses MC-SS
modulation scheme.It is observed that when a branch is added in the
link between sending and receiving end of an indoor channel an
average of 2.5dB power loss is found. In additional, when the branch
is added at a node an average of 1dB power loss is found.
Additionally when the terminal impedances of the branch change
from line characteristic impedance to impedance either higher or
lower values the channel performances were tremendously improved.
For example changing terminal load from characteristic impedance
(85 .) to 5 . the signal to noise ratio (SNR) required to attain the
same performances were decreased from 37dB to 24dB respectively.
Also, changing the terminal load from channel characteristic
impedance (85 .) to very higher impedance (1600 .) the SNR
required to maintain the same performances were decreased from
37dB to 23dB. The result concludes that MC-SS performs better
compared with OFDM techniques in all aspects and especially when
the channel is terminated in either higher or lower impedances.
Abstract: This paper focuses on assessment of air pollution in Umm-Alhyman, Kuwait, which is located south to oil refineries, power station, oil field, and highways. The measurements were made over a period of four days in March and July in 2001, 2004, and 2008. The measured pollutants included methanated and nonmethanated hydrocarbons (MHC, NMHC), CO, CO2, SO2, NOX, O3, and PM10. Also, meteorological parameters were measured, which includes temperature, wind speed and direction, and solar radiation. Over the study period, data analysis showed increase in measured SO2, NOX and CO by factors of 1.2, 5.5 and 2, respectively. This is explained in terms of increase in industrial activities, motor vehicle density, and power generation. Predictions of the measured data were made by the ISC-AERMOD software package and by using the ISCST3 model option. Finally, comparison was made between measured data against international standards.
Abstract: Solar energy is not only sustainable but also a clean
alternative to be used as source of high temperature heat for many
processes and power generation. However, the major drawback of
solar energy is its transient nature. Especially in solar
thermochemical processing, it is crucial to maintain constant or semiconstant
temperatures inside the solar reactor. In our laboratory, we
have developed a mechanism allowing us to achieve semi-constant
temperature inside the solar reactor. In this paper, we introduce the
concept along with some updated designs and provide the optical
analysis of the concept under various incoming flux.
Abstract: As embedded and portable systems were emerged power consumption of circuits had been major challenge. On the other hand latency as determines frequency of circuits is also vital task. Therefore, trade off between both of them will be desirable. Modulo 2n+1 adders are important part of the residue number system (RNS) based arithmetic units with the interesting moduli set (2n-1,2n, 2n+1). In this manuscript we have introduced novel binary representation to the design of modulo 2n+1 adder. VLSI realization of proposed architecture under 180 nm full static CMOS technology reveals its superiority in terms of area, power consumption and power-delay product (PDP) against several peer existing structures.
Abstract: The convergence of heterogeneous wireless access technologies characterizes the 4G wireless networks. In such converged systems, the seamless and efficient handoff between
different access technologies (vertical handoff) is essential and remains a challenging problem. The heterogeneous co-existence of access technologies with largely different characteristics creates a decision problem of determining the “best" available network at
“best" time to reduce the unnecessary handoffs. This paper proposes a dynamic decision model to decide the “best" network at “best"
time moment to handoffs. The proposed dynamic decision model make the right vertical handoff decisions by determining the “best"
network at “best" time among available networks based on, dynamic
factors such as “Received Signal Strength(RSS)" of network and
“velocity" of mobile station simultaneously with static factors like Usage Expense, Link capacity(offered bandwidth) and power
consumption. This model not only meets the individual user needs but also improve the whole system performance by reducing the unnecessary handoffs.
Abstract: In this paper, Optimum adaptive loading algorithms
are applied to multicarrier system with Space-Time Block Coding
(STBC) scheme associated with space-time processing based on
singular-value decomposition (SVD) of the channel matrix over
Rayleigh fading channels. SVD method has been employed in
MIMO-OFDM system in order to overcome subchannel interference.
Chaw-s and Compello-s algorithms have been implemented to obtain
a bit and power allocation for each subcarrier assuming instantaneous
channel knowledge. The adaptive loaded SVD-STBC scheme is
capable of providing both full-rate and full-diversity for any number
of transmit antennas. The effectiveness of these techniques has
demonstrated through the simulation of an Adaptive loaded SVDSTBC
system, and the comparison shown that the proposed
algorithms ensure better performance in the case of MIMO.
Abstract: Routing in MANET is extremely challenging because
of MANETs dynamic features, its limited bandwidth, frequent
topology changes caused by node mobility and power energy
consumption. In order to efficiently transmit data to destinations, the
applicable routing algorithms must be implemented in mobile ad-hoc
networks. Thus we can increase the efficiency of the routing by
satisfying the Quality of Service (QoS) parameters by developing
routing algorithms for MANETs. The algorithms that are inspired by
the principles of natural biological evolution and distributed
collective behavior of social colonies have shown excellence in
dealing with complex optimization problems and are becoming more
popular. This paper presents a survey on few meta-heuristic
algorithms and naturally-inspired algorithms.
Abstract: Electricity market activities and a growing demand for electricity have led to heavily stressed power systems. This requires operation of the networks closer to their stability limits. Power system operation is affected by stability related problems, leading to unpredictable system behavior. Voltage stability refers to the ability of a power system to sustain appropriate voltage levels through large and small disturbances. Steady-state voltage stability is concerned with limits on the existence of steady-state operating points for the network. FACTS devices can be utilized to increase the transmission capacity, the stability margin and dynamic behavior or serve to ensure improved power quality. Their main capabilities are reactive power compensation, voltage control and power flow control. Among the FACTS controllers, Static Var Compensator (SVC) provides fast acting dynamic reactive compensation for voltage support during contingency events. In this paper, voltage stability assessment with appropriate representations of tap-changer transformers and SVC is investigated. Integrating both of these devices is the main topic of this paper. Effect of the presence of tap-changing transformers on static VAR compensator controller parameters and ratings necessary to stabilize load voltages at certain values are highlighted. The interrelation between transformer off nominal tap ratios and the SVC controller gains and droop slopes and the SVC rating are found. P-V curves are constructed to calculate loadability margins.
Abstract: A research study was conducted with an objective to propose a collaborative business strategy of a oil and gas trading company, representing PPT Energy Trading Co., Ltd., with its shareholder, especially electricity and power supply companies for LNG Form of Coal Bed Methane in B2B Transaction. Collaborative business strategy is a strategy to collaborate with other organizations due to have future benefits in both parties, or achieve the business objective through the collaboration of business, its strategy and partners. A structured interview was established to collect the required primary data from the company. Not only interview, but also company’s business plan and annual report were collected and analyzed for the company’s current condition. As the result, this research shows a recommendation to propose a new collaborative strategy with limiting its target market, diversifying product, conducting new business model, and considering other stakeholders.
Abstract: This paper presents design and characterization of a
microaccelerometer designated for integration into cataract surgical
probe to detect hardness of different eye tissues during cataract
surgery. Soft posterior lens capsule of eye can be easily damaged in
comparison with hard opaque lens since the surgeon can not see
directly behind cutting needle during the surgery. Presence of
microsensor helps the surgeon to avoid rupturing posterior lens
capsule which if occurs leads to severe complications such as
glaucoma, infection, or even blindness. The microsensor having
overall dimensions of 480 μm x 395 μm is able to deliver significant
capacitance variations during encountered vibration situations which
makes it capable to distinguish between different types of tissue.
Integration of electronic components on chip ensures high level of
reliability and noise immunity while minimizes space and power
requirements. Physical characteristics and results on performance
testing, proves integration of microsensor as an effective tool to aid
the surgeon during this procedure.
Abstract: A novel three-phase active power filter (APF) circuit with photovoltaic (PV) system to improve the quality of service and to reduce the capacity of energy storage capacitor is presented. The energy balance concept and sampling technique were used to simplify the calculation algorithm for the required utility source current and to control the voltage of the energy storage capacitor. The feasibility was verified by using the Pspice simulations and experiments. When the APF mode was used during non-operational period, not only the utilization rate, power factor and power quality could be improved, but also the capacity of energy storage capacitor could sparing. As the results, the advantages of the APF circuit are simplicity of control circuits, low cost, and good transient response.
Abstract: Optical 1x12 fused-taper-twisted polymer optical fiber (POF) couplers has been fabricated by a perform technique. Characterization of the coupler which proposed to be used in passive night vision application to tracking a blind sport area was reported. During the development process of fused-taper-twisted POF couplers was carried out, red LED fully utilized to be injected into the couplers to test the quality of fabricated couplers. Some characterization parameters, such as optical output power, POFs attenuation characteristics and power losses on the network were observed. The maximum output power efficiency of the coupler is about 40%, but it can be improved gradually through experience and practice.