Abstract: The purpose of this work is fast design optimization of
the seal chamber. The study includes the mass transfer between lower
and upper chamber on seal chamber for hot water application pumps.
The use of Fluent 12.1 commercial code made it possible to capture
complex flow with heat-mass transfer, radiation, Tailor instability,
and buoyancy effect. Realizable k-epsilon model was used for
turbulence modeling. Radiation heat losses were taken into account.
The temperature distribution at seal region is predicted with respect
to heat addition.
Results show the possibilities of the model simplifications by
excluding the water domain in low chamber from calculations. CFD
simulations permit to improve seal chamber design to meet target
water temperature around the seal. This study can be used for the
analysis of different seal chamber configurations.
Abstract: This paper introduces an adiabatic register file based
on two-phase CPAL (Complementary Pass-Transistor Adiabatic
Logic circuits) with power-gating scheme, which can operate on a
single-phase power clock. A 32×32 single-phase adiabatic register file
with power-gating scheme has been implemented with TSMC 0.18μm
CMOS technology. All the circuits except for the storage cells employ
two-phase CPAL circuits, and the storage cell is based on the
conventional memory one. The two-phase non-overlap power-clock
generator with power-gating scheme is used to supply the proposed
adiabatic register file. Full-custom layouts are drawn. The energy and
functional simulations have been performed using the net-list
extracted from their layouts. Compared with the traditional static
CMOS register file, HSPICE simulations show that the proposed
adiabatic register file can work very well, and it attains about 73%
energy savings at 100 MHz.
Abstract: This paper describes a low-voltage and low-power
channel selection analog front end with continuous-time low pass
filters and highly linear programmable gain amplifier (PGA). The
filters were realized as balanced Gm-C biquadratic filters to achieve a
low current consumption. High linearity and a constant wide
bandwidth are achieved by using a new transconductance (Gm) cell.
The PGA has a voltage gain varying from 0 to 65dB, while
maintaining a constant bandwidth. A filter tuning circuit that requires
an accurate time base but no external components is presented.
With a 1-Vrms differential input and output, the filter achieves
-85dB THD and a 78dB signal-to-noise ratio. Both the filter and PGA
were implemented in a 0.18um 1P6M n-well CMOS process. They
consume 3.2mW from a 1.8V power supply and occupy an area of
0.19mm2.
Abstract: As originally designed for wired networks, TCP (transmission control protocol) congestion control mechanism is triggered into action when packet loss is detected. This implicit assumption for packet loss mostly due to network congestion does not work well in Mobile Ad Hoc Network, where there is a comparatively high likelihood of packet loss due to channel errors and node mobility etc. Such non-congestion packet loss, when dealt with by congestion control mechanism, causes poor TCP performance in MANET. In this study, we continue to investigate the impact of the interaction between transport protocols and on-demand routing protocols on the performance and stability of 802.11 multihop networks. We evaluate the important wireless networking events caused routing change, and propose a cross layer method to delay the unnecessary routing changes, only need to add a sensitivity parameter α , which represents the on-demand routing-s reaction to link failure of MAC layer. Our proposal is applicable to the plain 802.11 networking environment, the simulation results that this method can remarkably improve the stability and performance of TCP without any modification on TCP and MAC protocol.
Abstract: This paper presents a methodology towards the emulation of the electrical power consumption of the RF device during the cellular phone/handset transmission mode using the LTE technology. The emulation methodology takes the physical environmental variables and the logical interface between the baseband and the RF system as inputs to compute the emulated power dissipation of the RF device. The emulated power, in between the measured points corresponding to the discrete values of the logical interface parameters is computed as a polynomial interpolation using polynomial basis functions. The evaluation of polynomial and spline curve fitting models showed a respective divergence (test error) of 8% and 0.02% from the physically measured power consumption. The precisions of the instruments used for the physical measurements have been modeled as intervals. We have been able to model the power consumption of the RF device operating at 5MHz using homotopy between 2 continuous power consumptions of the RF device operating at the bandwidths 3MHz and 10MHz.
Abstract: In this paper, Lattice Boltzmann Method (LBM) is used to study laminar flow with mixed convection heat transfer inside a two-dimensional inclined lid-driven rectangular cavity with aspect ratio AR = 3. Bottom wall of the cavity is maintained at lower temperature than the top lid, and its vertical walls are assumed insulated. Top lid motion results in fluid motion inside the cavity. Inclination of the cavity causes horizontal and vertical components of velocity to be affected by buoyancy force. To include this effect, calculation procedure of macroscopic properties by LBM is changed and collision term of Boltzmann equation is modified. A computer program is developed to simulate this problem using BGK model of lattice Boltzmann method. The effects of the variations of Richardson number and inclination angle on the thermal and flow behavior of the fluid inside the cavity are investigated. The results are presented as velocity and temperature profiles, stream function contours and isotherms. It is concluded that LBM has good potential to simulate mixed convection heat transfer problems.
Abstract: In this paper, we investigate the study of techniques
for scheduling users for resource allocation in the case of multiple
input and multiple output (MIMO) packet transmission systems. In
these systems, transmit antennas are assigned to one user or
dynamically to different users using spatial multiplexing. The
allocation of all transmit antennas to one user cannot take full
advantages of multi-user diversity. Therefore, we developed the case
when resources are allocated dynamically. At each time slot users
have to feed back their channel information on an uplink feedback
channel. Channel information considered available in the schedulers
is the zero forcing (ZF) post detection signal to interference plus
noise ratio. Our analysis study concerns the round robin and the
opportunistic schemes.
In this paper, we present an overview and a complete capacity
analysis of these schemes. The main results in our study are to give
an analytical form of system capacity using the ZF receiver at the
user terminal. Simulations have been carried out to validate all
proposed analytical solutions and to compare the performance of
these schemes.
Abstract: This paper presents a methodology for operational and
economic characteristics based evaluation and selection of a power
plant using Graph theoretic approach. A universal evaluation index
on the basis of Operational and economics characteristics of a plant is
proposed which evaluates and ranks the various types of power plants.
The index thus obtained from the pool of operational characteristics
of the power plant attributes Digraph. The Digraph is developed
considering Operational and economics attributes of the power plants
and their relative importance for their smooth operation, installation
and commissioning and prioritizing their selection. The sensitivity
analysis of the attributes towards the objective has also been carried
out in order to study the impact of attributes over the desired outcome
i.e. the universal operational-economics index of the power plant.
Abstract: In this paper, we have developed a method to
compute fractal dimension (FD) of discrete time signals, in the
time domain, by modifying the box-counting method. The size
of the box is dependent on the sampling frequency of the
signal. The number of boxes required to completely cover the
signal are obtained at multiple time resolutions. The time
resolutions are made coarse by decimating the signal. The loglog
plot of total number of boxes required to cover the curve
versus size of the box used appears to be a straight line, whose
slope is taken as an estimate of FD of the signal. The results
are provided to demonstrate the performance of the proposed
method using parametric fractal signals. The estimation
accuracy of the method is compared with that of Katz, Sevcik,
and Higuchi methods. In addition, some properties of the FD
are discussed.
Abstract: Electromyography (EMG) signal processing has been investigated remarkably regarding various applications such as in rehabilitation systems. Specifically, wavelet transform has served as a powerful technique to scrutinize EMG signals since wavelet transform is consistent with the nature of EMG as a non-stationary signal. In this paper, the efficiency of wavelet transform in surface EMG feature extraction is investigated from four levels of wavelet decomposition and a comparative study between different mother wavelets had been done. To recognize the best function and level of wavelet analysis, two evaluation criteria, scatter plot and RES index are recruited. Hereupon, four wavelet families, namely, Daubechies, Coiflets, Symlets and Biorthogonal are studied in wavelet decomposition stage. Consequently, the results show that only features from first and second level of wavelet decomposition yields good performance and some functions of various wavelet families can lead to an improvement in separability class of different hand movements.
Abstract: There are many debates now regarding undervalued
and overvalued currencies currently traded on the world financial
market. This paper contributes to these debates from a theoretical
point of view. We present the three most commonly used methods of
estimating the equilibrium real effective exchange rate (REER):
macroeconomic balance approach, external sustainability approach
and equilibrium real effective exchange rate approach in the reduced
form. Moreover, we discuss key concepts of the calculation of the
real exchange rate (RER) based on applied explanatory variables:
nominal exchange rates, terms of trade and tradable and non-tradable
goods. Last but not least, we discuss the three main driving forces
behind real exchange rates movements which include terms of trade,
relative productivity growth and the interest rate differential.
Abstract: The hydraulic actuated excavator, being a non-linear
mobile machine, encounters many uncertainties. There are
uncertainties in the hydraulic system in addition to the uncertain
nature of the load. The simulation results obtained in this study show
that there is a need for intelligent control of such machines and in
particular interval type-2 fuzzy controller is most suitable for
minimizing the position error of a typical excavator-s bucket under
load variations. We consider the model parameter uncertainties such
as hydraulic fluid leakage and friction. These are uncertainties which
also depend up on the temperature and alter bulk modulus and
viscosity of the hydraulic fluid. Such uncertainties together with the
load variations cause chattering of the bucket position. The interval
type-2 fuzzy controller effectively eliminates the chattering and
manages to control the end-effecter (bucket) position with positional
error in the order of few millimeters.
Abstract: In this paper a three dimensional thermal model of
high breaking capacity fuse with unequal fuse links is proposed for
both steady-state or transient conditions. The influence of ambient
temperature and electric current on the temperature distribution
inside the fuse, has been investigated. A thermal analysis of the
unbalanced distribution of the electric current through the fuse
elements and their influence on fuse link temperature rise, has been
performed. To validate the three dimensional thermal model, some
experimental tests have been done. There is a good correlation
between experimental and simulation results.
Abstract: This paper demonstrates an effort of a serviceoriented
engineering department in improving the sharing and
transfer of knowledge. Although the department consist of only six
employees, but it provides services in various chemical application in
an oil and gas business. The services provided span across Asia
Pacific region mainly Indonesia, Myanmar, Vietnam, Brunei,
Thailand and Singapore. Currently there are no effective tools or
integrated systems that support the sharing or transfer and
maintenance of knowledge so the department has considered
preserving this valuable knowledge by developing a Knowledge
Management System (KMS). This paper presents the development of
a KMS to support the sharing of knowledge in a service-oriented
engineering department of an oil and gas company. The embedded
features in the KMS like blog and forum will encourage iterative
process of knowledge sharing among the employees in the
department. The information and knowledge being shared, discussed
and communicated will be then achieved for future re-use. The re-use
of the knowledge allows the department to reduce redundant efforts
in providing consistent, up-to-date and cost effective of the best
solution to the its clients.
Abstract: This paper presents a method for the optimal
allocation of Distributed generation in distribution systems. In this
paper, our aim would be optimal distributed generation allocation for
voltage profile improvement and loss reduction in distribution
network. Genetic Algorithm (GA) was used as the solving tool,
which referring two determined aim; the problem is defined and
objective function is introduced. Considering to fitness values
sensitivity in genetic algorithm process, there is needed to apply load
flow for decision-making. Load flow algorithm is combined
appropriately with GA, till access to acceptable results of this
operation. We used MATPOWER package for load flow algorithm
and composed it with our Genetic Algorithm. The suggested method
is programmed under MATLAB software and applied ETAP
software for evaluating of results correctness. It was implemented on
part of Tehran electricity distributing grid. The resulting operation of
this method on some testing system is illuminated improvement of
voltage profile and loss reduction indexes.
Abstract: For any country the project management has been a
vital part for its development. The highly competitive business world
has created tremendous pressure on the project managers to achieve
success. The pressure is derived from survival and profit building in
business organizations which compels the project managers to pursue
unethical practices. As a result unethical activities in business
projects can be found easily where situations or issues arise due to
dubious business practice, high corruption, or absolute violation of
the law. The recent spur on Commonwealth games to be organized in
New Delhi indicates towards the same. It has been seen that the
project managers mainly focus on cost, time, and quality rather than
social impact and long term effects of the project. Surprisingly the
literature as well as the practitioner-s perspective also does not
identify the role of ethics in project success. This paper identifies
ethics as the fourth most important dimension in the project based
organizations. The paper predicts that the approach of considering
ethics will result in sustainability of the project. It will increase
satisfaction and loyalty of the customers as well as create harmony,
trust, brotherhood, values and morality among the team members.
This paper is conceptual in nature as inadequate literature exists
linking the project success with an ethical approach.
Abstract: In this paper, the issue of pth moment exponential stability of stochastic recurrent neural network with distributed time delays is investigated. By using the method of variation parameters, inequality techniques, and stochastic analysis, some sufficient conditions ensuring pth moment exponential stability are obtained. The method used in this paper does not resort to any Lyapunov function, and the results derived in this paper generalize some earlier criteria reported in the literature. One numerical example is given to illustrate the main results.
Abstract: Hierarchical high-level PNs (HHPNs) with time
versions are a useful tool to model systems in a variety of application
domains, ranging from logistics to complex workflows. This paper
addresses an application domain which is receiving more and more
attention: procedure that arranges the final inpatient charge in
payment-s office and their management. We shall prove that Petri net
based analysis is able to improve the delays during the procedure, in
order that inpatient charges could be more reliable and on time.
Abstract: In this contribution a newly developed elearning environment is presented, which incorporates Intelligent Agents and Computational Intelligence Techniques. The new e-learning environment is constituted by three parts, the E-learning platform Front-End, the Student Questioner Reasoning and the Student Model Agent. These parts are distributed geographically in dispersed computer servers, with main focus on the design and development of these subsystems through the use of new and emerging technologies. These parts are interconnected in an interoperable way, using web services for the integration of the subsystems, in order to enhance the user modelling procedure and achieve the goals of the learning process.
Abstract: Almost all universities include some form of assignment in their courses. The assignments are either carried out in either in groups or individually. To effectively manage these submitted assignments, a well-designed assignment submission system is needed, hence the need for an online assignment submission system to facilitate the distribution, and collection of assignments on due dates. The objective of such system is to facilitate interaction of lecturers and students for assessment and grading purposes. The aim of this study was to create a web based online assignment submission system for University of Mauritius. The system was created to eliminate the traditional process of giving an assignment and collecting the answers for the assignment. Lecturers can also create automated assessment to assess the students online. Moreover, the online submission system consists of an automatic mailing system which acts as a reminder for students about the deadlines of the posted assignments. System was tested to measure its acceptance rate among both student and lecturers.