Abstract: The mixture formation prior to the ignition process
plays as a key element in the diesel combustion. Parametric studies of
mixture formation and ignition process in various injection parameter
has received considerable attention in potential for reducing
emissions. Purpose of this study is to clarify the effects of injection
pressure on mixture formation and ignition especially during ignition
delay period, which have to be significantly influences throughout the
combustion process and exhaust emissions. This study investigated
the effects of injection pressure on diesel combustion fundamentally
using rapid compression machine. The detail behavior of mixture
formation during ignition delay period was investigated using the
schlieren photography system with a high speed camera. This method
can capture spray evaporation, spray interference, mixture formation
and flame development clearly with real images. Ignition process and
flame development were investigated by direct photography method
using a light sensitive high-speed color digital video camera. The
injection pressure and air motion are important variable that strongly
affect to the fuel evaporation, endothermic and prolysis process
during ignition delay. An increased injection pressure makes spray tip
penetration longer and promotes a greater amount of fuel-air mixing
occurs during ignition delay. A greater quantity of fuel prepared
during ignition delay period thus predominantly promotes more rapid
heat release.
Abstract: Combustion of sprays is of technological importance, but its flame behavior is not fully understood. Furthermore, the multiplicity of dependent variables such as pressure, temperature, equivalence ratio, and droplet sizes complicates the study of spray combustion. Fundamental study on the influence of the presence of liquid droplets has revealed that laminar flames within aerosol mixtures more readily become unstable than for gaseous ones and this increases the practical burning rate. However, fundamental studies on turbulent flames of aerosol mixtures are limited particularly those under near mono-dispersed droplet conditions. In the present work, centrally ignited expanding flames at near atmospheric pressures are employed to quantify the burning rates in gaseous and aerosol flames. Iso-octane-air aerosols are generated by expansion of the gaseous pre-mixture to produce a homogeneously distributed suspension of fuel droplets. The effects of the presence of droplets and turbulence velocity in relation to the burning rates of the flame are also investigated.
Abstract: The Information and Communication Technologies
(ICTs), and the Wide World Web (WWW) have fundamentally
altered the practice of teaching and learning world wide. Many
universities, organizations, colleges and schools are trying to apply
the benefits of the emerging ICT. In the early nineties the term
learning object was introduced into the instructional technology
vernacular; the idea being that educational resources could be broken
into modular components for later combination by instructors,
learners, and eventually computes into larger structures that would
support learning [1]. However in many developing countries, the use
of ICT is still in its infancy stage and the concept of learning object
is quite new. This paper outlines the learning object design
considerations for developing countries depending on learning
environment.
Abstract: Since the feasibility study of R&D programs have been
initiated for efficient public R&D investments, year 2008, feasibility
studies have improved in terms of precision. Although experience
related to these studies of R&D programs have increased to a certain
point, still methodological improvement is required. The feasibility
studies of R&D programs are consisted of various viewpoints, such as
technology, policy, and economics. This research is to provide
improvement methods to the economic perspective; especially the cost
estimation process of R&D activities. First of all, the fundamental
concept of cost estimation is reviewed. After the review, a statistical
and econometric analysis method is applied as empirical analysis.
Conclusively, limitations and further research directions are provided.
Abstract: This article provides some insight into the
implementation of the national ID programme in the United Arab
Emirates (UAE). The fundamental aim is to contribute to the
existing body of knowledge in the field, as it sheds light on some of
the lessons learned from the programme that is believed to widening
the knowledge horizons of those involved in such initiatives.
Abstract: This paper presents the control performance of a high-precision positioning device using the hybrid actuator composed of a piezoelectric (PZT) actuator and a voice-coil motor (VCM). The combined piezo-VCM actuator features two main characteristics: a large operation range due to long stroke of the VCM, and high precision and heavy load positioning ability due to PZT impact force. A one-degree-of-freedom (DOF) experimental setup was configured to examine the fundamental characteristics, and the control performance was effectively demonstrated by using a switching controller. In rough positioning state, an integral variable structure controller (IVSC) was used for the VCM to conduct long range of operation; in precision positioning state, an impact force controller (IFC) for the PZT actuator coupled with presliding states of the sliding table was used to obtain high-precision position control and achieve both forward and backward actuations. The experimental results showed that the sliding table having a mass of 881g and with a preload of 10 N was successfully positioned within the positioning accuracy of 10 nm in both forward and backward position controls.
Abstract: IEEE 802.11e is the enhanced version of the IEEE
802.11 MAC dedicated to provide Quality of Service of wireless
network. It supports QoS by the service differentiation and
prioritization mechanism. Data traffic receives different priority
based on QoS requirements. Fundamentally, applications are divided
into four Access Categories (AC). Each AC has its own buffer queue
and behaves as an independent backoff entity. Every frame with a
specific priority of data traffic is assigned to one of these access
categories. IEEE 802.11e EDCA (Enhanced Distributed Channel
Access) is designed to enhance the IEEE 802.11 DCF (Distributed
Coordination Function) mechanisms by providing a distributed
access method that can support service differentiation among
different classes of traffic. Performance of IEEE 802.11e MAC layer
with different ACs is evaluated to understand the actual benefits
deriving from the MAC enhancements.
Abstract: Frequent patterns are patterns such as sets of features or items that appear in data frequently. Finding such frequent patterns has become an important data mining task because it reveals associations, correlations, and many other interesting relationships hidden in a dataset. Most of the proposed frequent pattern mining algorithms have been implemented with imperative programming languages such as C, Cµ, Java. The imperative paradigm is significantly inefficient when itemset is large and the frequent pattern is long. We suggest a high-level declarative style of programming using a functional language. Our supposition is that the problem of frequent pattern discovery can be efficiently and concisely implemented via a functional paradigm since pattern matching is a fundamental feature supported by most functional languages. Our frequent pattern mining implementation using the Haskell language confirms our hypothesis about conciseness of the program. The performance studies on speed and memory usage support our intuition on efficiency of functional language.
Abstract: The paper presents the results of research on trends in shaping of multifamily buildings in Poland on the example of Wrocław, after Polish accession to the European Union. The study is conducted within the research project: “Trends in creating of multifamily housing development since 2004, on the Wrocław study case" supported by Polish Ministry of Science and Higher Education and will be completed in November 2011. The research involves multifamily buildings completed in the last decade, in term of fundamental urbanization factors such as: building-s coefficient area, useable area, green area (biologically active surface), intensity of building development, amount of dwellings, dwelling area, amount of parking places, numbers of floors, etc. The analysis of these indicators was conducted based on the date obtained in the study of approximately one hundred new housing units, completed in Wroclaw. The analysis attempts to formulate the main trends in creating of housing policy in Poland during the last 10 years in reference to local urban policy.
Abstract: The use of e-business in small and medium-sized
enterprises (SMEs) has been recently received an enormous attention
in information systems research by both academic and practitioners.
With the adoption of new and efficient technologies to enhance
businesses, Thai SMEs should be able to compete worldwide.
Unfortunately, most of the owners are not used to new technologies.
It is clear that most Thai SMEs prefer to work manually rather than
electronically. This paper aims to provide a fundamental conceptual
framework for E-business adoption by Thai SMEs. Rooted in
Knowledge transfer model, several factors are identified, which drive
and enable e-business adoption. By overlooking the benefits
associated with implementing new technologies, it is difficult for
Thai SMEs to perform well enough to compete globally. The paper
also helps Thai SMEs to understand factors related to E-business
adoption.
Abstract: Text Mining is an important step of Knowledge
Discovery process. It is used to extract hidden information from notstructured
o semi-structured data. This aspect is fundamental because
much of the Web information is semi-structured due to the nested
structure of HTML code, much of the Web information is linked,
much of the Web information is redundant. Web Text Mining helps
whole knowledge mining process to mining, extraction and
integration of useful data, information and knowledge from Web
page contents.
In this paper, we present a Web Text Mining process able to
discover knowledge in a distributed and heterogeneous multiorganization
environment. The Web Text Mining process is based on
flexible architecture and is implemented by four steps able to
examine web content and to extract useful hidden information
through mining techniques. Our Web Text Mining prototype starts
from the recovery of Web job offers in which, through a Text Mining
process, useful information for fast classification of the same are
drawn out, these information are, essentially, job offer place and
skills.
Abstract: Ovshinsky initiated scientific research in the field of
amorphous and disordered materials that continues to this day. The
Ovshinsky Effect where the resistance of thin GST films is
significantly reduced upon the application of low voltage is of
fundamental importance in phase-change - random access memory
(PC-RAM) devices.GST stands for GdSbTe chalcogenide type
glasses.However, the Ovshinsky Effect is not without controversy.
Ovshinsky thought the resistance of GST films is reduced by the
redistribution of charge carriers; whereas, others at that time including
many PC-RAM researchers today argue that the GST resistance
changes because the GST amorphous state is transformed to the
crystalline state by melting, the heat supplied by external heaters. In
this controversy, quantum mechanics (QM) asserts the heat capacity of
GST films vanishes, and therefore melting cannot occur as the heat
supplied cannot be conserved by an increase in GST film
temperature.By precluding melting, QM re-opens the controversy
between the melting and charge carrier mechanisms. Supporting
analysis is presented to show that instead of increasing GST film
temperature, conservation proceeds by the QED induced creation of
photons within the GST film, the QED photons confined by TIR. QED
stands for quantum electrodynamics and TIR for total internal
reflection. The TIR confinement of QED photons is enhanced by the
fact the absorbedheat energy absorbed in the GST film is concentrated
in the TIR mode because of their high surface to volume ratio. The
QED photons having Planck energy beyond the ultraviolet produce
excitons by the photoelectric effect, the electrons and holes of which
reduce the GST film resistance.
Abstract: The Automatic Speech Recognition (ASR) applied to
Arabic language is a challenging task. This is mainly related to the
language specificities which make the researchers facing multiple
difficulties such as the insufficient linguistic resources and the very
limited number of available transcribed Arabic speech corpora. In
this paper, we are interested in the development of a HMM-based
ASR system for Standard Arabic (SA) language. Our fundamental
research goal is to select the most appropriate acoustic parameters
describing each audio frame, acoustic models and speech recognition
unit. To achieve this purpose, we analyze the effect of varying frame
windowing (size and period), acoustic parameter number resulting
from features extraction methods traditionally used in ASR, speech
recognition unit, Gaussian number per HMM state and number of
embedded re-estimations of the Baum-Welch Algorithm. To evaluate
the proposed ASR system, a multi-speaker SA connected-digits
corpus is collected, transcribed and used throughout all experiments.
A further evaluation is conducted on a speaker-independent continue
SA speech corpus. The phonemes recognition rate is 94.02% which is
relatively high when comparing it with another ASR system
evaluated on the same corpus.
Abstract: Large-scale systems such as Grids offer
infrastructures for both data distribution and parallel processing. The
use of Grid infrastructures is a more recent issue that is already
impacting the Distributed Database Management System industry. In
DBMS, distributed query processing has emerged as a fundamental
technique for ensuring high performance in distributed databases.
Database placement is particularly important in large-scale systems
because it reduces communication costs and improves resource
usage. In this paper, we propose a dynamic database placement
policy that depends on query patterns and Grid sites capabilities. We
evaluate the performance of the proposed database placement policy
using simulations. The obtained results show that dynamic database
placement can significantly improve the performance of distributed
query processing.
Abstract: There is need to explore emerging technologies based on carbon nanotube electronics as the MOS technology is approaching its limits. As MOS devices scale to the nano ranges, increased short channel effects and process variations considerably effect device and circuit designs. As a promising new transistor, the Carbon Nanotube Field Effect Transistor(CNTFET) avoids most of the fundamental limitations of the Traditional MOSFET devices. In this paper we present the analysis and comparision of a Carbon Nanotube FET(CNTFET) based 10(A current mirror with MOSFET for 32nm technology node. The comparision shows the superiority of the former in terms of 97% increase in output resistance,24% decrease in power dissipation and 40% decrease in minimum voltage required for constant saturation current. Furthermore the effect on performance of current mirror due to change in chirality vector of CNT has also been investigated. The circuit simulations are carried out using HSPICE model.
Abstract: Nondestructive testing in engineering is an inverse
Cauchy problem for Laplace equation. In this paper the problem
of nondestructive testing is expressed by a Laplace-s equation with
third-kind boundary conditions. In order to find unknown values on
the boundary, the method of fundamental solution is introduced and
realized. Because of the ill-posedness of studied problems, the TSVD
regularization technique in combination with L-curve criteria and
Generalized Cross Validation criteria is employed. Numerical results
are shown that the TSVD method combined with L-curve criteria is
more efficient than the TSVD method combined with GCV criteria.
The abstract goes here.
Abstract: In this article an isotropic linear elastic half-space with
a cylindrical cavity of finite length is considered to be under the
effect of a ring shape time-harmonic torsion force applied at an
arbitrary depth on the surface of the cavity. The equation of
equilibrium has been written in a cylindrical coordinate system. By
means of Fourier cosine integral transform, the non-zero
displacement component is obtained in the transformed domain. With
the aid of the inversion theorem of the Fourier cosine integral
transform, the displacement is obtained in the real domain. With the
aid of boundary conditions, the involved boundary value problem for
the fundamental solution is reduced to a generalized Cauchy singular
integral equation. Integral representation of the stress and
displacement are obtained, and it is shown that their degenerated
form to the static problem coincides with existing solutions in the
literature.
Abstract: A neuron can emit spikes in an irregular time basis and by averaging over a certain time window one would ignore a lot of information. It is known that in the context of fast information processing there is no sufficient time to sample an average firing rate of the spiking neurons. The present work shows that the spiking neurons are capable of computing the radial basis functions by storing the relevant information in the neurons' delays. One of the fundamental findings of the this research also is that when using overlapping receptive fields to encode the data patterns it increases the network-s clustering capacity. The clustering algorithm that is discussed here is interesting from computer science and neuroscience point of view as well as from a perspective.
Abstract: Route bus system is one of fundamental transportation device for aged people and students, and has an important role in every province. However, passengers decrease year by year, therefore the authors have developed the system called "Bus-Net" as a web application to sustain the public transport. But there are two problems in Bus-Net. One is the user interface that does not consider the variety of the device, and the other is the path planning system that dose not correspond to the on-demand bus. Then, Bus-Net was improved to be able to utilize the variety of the device, and a new function corresponding to the on-demand bus was developed.
Abstract: This paper presents the experimental results of
leakage current waveforms which appears on porcelain insulator
surface due to existence of artificial pollutants. The tests have been
done using the chemical compounds of NaCl, Na2SiO3, H2SO4, CaO,
Na2SO4, KCl, Al2SO4, MgSO4, FeCl3, and TiO2. The insulator
surface was coated with those compounds and dried. Then, it was
tested in the chamber where the high voltage was applied. Using
correspondence analysis, the result indicated that the fundamental
harmonic of leakage current was very close to the applied voltage
and third harmonic leakage current was close to the yielded leakage
current amplitude. The first harmonic power was correlated to first
harmonic amplitude of leakage current, and third harmonic power
was close to third harmonic one. The chemical compounds of H2SO4
and Na2SiO3 affected to the power factor of around 70%. Both are the
most conductive, due to the power factor drastically increase among
the chemical compounds.