Abstract: Automatic tube current modulation (ATCM) systems are available for all CT manufacturers and are used for the majority of patients. Understanding how the systems work and their influence on patient dose and image quality is important for CT users, in order to gain the most effective use of the systems. In the present study, a new phantom was used for evaluating dose distribution and image quality under the ATCM operation for the Toshiba Aquilion 64 CT scanner using different ATCM options and a fixed mAs technique. A routine chest, abdomen and pelvis (CAP) protocol was selected for study and Gafchromic film was used to measure entrance surface dose (ESD), peripheral dose and central axis dose in the phantom. The results show the dose reductions achievable with various ATCM options, in relation with the target noise. The doses and image noise distribution were more uniform when the ATCM system was implemented compared with the fixed mAs technique. The lower limit set for the tube current will affect the modulations especially for the lower dose option. This limit prevented the tube current being reduced further and therefore the lower dose ATCM setting resembled a fixed mAs technique. Selection of a lower tube current limit is likely to reduce doses for smaller patients in scans of chest and neck regions.
Abstract: The motivation for adaptive modulation and coding is
to adjust the method of transmission to ensure that the maximum
efficiency is achieved over the link at all times. The receiver
estimates the channel quality and reports it back to the transmitter.
The transmitter then maps the reported quality into a link mode. This
mapping however, is not a one-to-one mapping. In this paper we
investigate a method for selecting the proper modulation scheme.
This method can dynamically adapt the mapping of the Signal-to-
Noise Ratio (SNR) into a link mode. It enables the use of the right
modulation scheme irrespective of changes in the channel conditions
by incorporating errors in the received data. We propose a Markov
model for this method, and use it to derive the average switching
thresholds and the average throughput. We show that the average
throughput of this method outperforms the conventional threshold
method.
Abstract: This paper proposes a location-aware system for
household robots which allows users to paste predefined paper tags at
different locations according to users- comprehension of the house. In this system a household robot may be aware of its location and the
attributes thereof by visually recognizing the tags when the robot is moving. This paper also presents a novel user interface to define a
moving path of the robot, which allows users to draw the path in the air
with a finger so as to generate commands for following motions.
Abstract: A novel biologically inspired controller for the autonomous
navigation of a mobile robot in an evasion task is
proposed. The controller takes advantage of the environment by
calculating a measure of danger and subsequently choosing the
parameters of a reinforcement learning based decision process.
Two different reinforcement learning algorithms were used: Qlearning
and Sarsa (λ). Simulations show that selecting dynamic
parameters reduce the time while executing the decision making
process, so the robot can obtain a policy to succeed in an escaping
task in a realistic time.
Abstract: In this study, the forty Thai medicinal plants were
used to screen the antibacterial activity against Campylobacter jejuni.
Crude 95% ethanolic extracts of each plant were prepared.
Antibacterial activity was investigated by the disc diffusion assay,
and MICs and MBCs were determined by broth microdilution. The
results of antibacterial screening showed that five plants have activity
against C.jejuni including Adenanthera pavonina L., Moringa
oleifera Lam., Annona squamosa L., Hibiscus sabdariffa L. and
Eupotorium odortum L. The extraction of A. pavonina L. and A.
squamosa L. produced an outstanding against C. jejuni, inhibiting
growth at 62.5-125 and 250-500 μg/mL, respectively. The MBCs of
two extracts were just 4-fold higher than MICs against C. jejuni,
suggesting the extracts are bactericidal against this species. These
results indicate that A. pavonina and A. squamosa could potentially
be used in modern applications aimed at treatment or prevention of
foodborne disease from C. jejuni.
Abstract: Culinary culture differences can cause health
problems for international tourists in Thailand. This paper drew upon
data collected from an international tourist survey conducted in
Bangkok, Thailand during summer of 2012. Summer is the period
that a variety food safety issues and incidents are often publicized in
Thailand. The survey targeted European Union tourists- concerns
toward a variety of food safety issues that they encountered during
their trip in Thailand. A total of 400 respondents were elicited as data
input for t-test, and one way ANOVA test. The findings revealed an
astonishing result that up to 46.5 percent of respondents were sick at
least one time or more in Thailand. However, the majority of
respondents trusted that the Thai hotel and Thai restaurants would
ensure food safety, but they did not trust street vendors to ensure food
safety. The level of food safety concern can be ranked from most
concern to least concern by using the value of mean scores as
follows: 1) artificial coloring, 2) use of preservatives, 3) antibiotics,
4) growth hormones, 5) chemical residues, and 6) bacterial
contamination. The overall mean score for level of concerns was
3.493 with standard deviation of 1.677 which did not indicate a very
high level of concern. In addition, the result for t-test and one way
ANOVA test revealed that there was not much effect from the
demographic differences to level of food safety concerns.
Abstract: This paper presents the mathematical model and
control strategy on DQ frame of shunt active power filter. The
structure of the shunt active power filter is the voltage source inverter
(VSI). The pulse width modulation (PWM) with PI controller is used
in the paper. The concept of DQ frame to apply with the shunt active
power filter is described. Moreover, the detail of the PI controller
design for two current loops and one voltage loop are fully explained.
The DQ axis with Fourier (DQF) method is applied to calculate the
reference currents on DQ frame. The simulation results show that the
control strategy and the design method presented in the paper can
provide the good performance of the shunt active power filter.
Moreover, the %THD of the source currents after compensation can
follow the IEEE Std.519-1992.
Abstract: Nowadays companies in all sectors are looking for the
sources of competitive advantages. Holistic marketing approach
searches for their emergence based on the integration of all
components and elements across the organization. Modern marketing
sees the sources of competitive advantage in implementing the latest
managerial practices, motivation, intelligent project management,
knowledge management, collaborative marketing, CSR and, in the
recent years, also in the business process optimization. With the use
of modern tools including business process management and business
process modelling the company can markedly increase its internal
efficiency which can lead not only to lowering the costs but to
creating the environment for optimal customer care, positive
corporate culture and for origination of innovations as well. In the
article the authors analyze the recent trend in this area and introduce
suggestions to companies to identify and optimize the key processes
that have a significant impact of the company´s competitiveness.
Abstract: The purpose of this research is to increase our
knowledge as regards how Small-and-Medium-Sized Enterprises
(SMEs) tackle ERP implementation projects to achieve successful
adoption and use of these systems within the organization. SMEs
have scare resources to handle these kinds of projects which have
proved to be risky and costly. There are several studies focusing on
ERP implementation in larger companies, however, few studies
report on challenges experienced by SMEs. Our research seeks to
bridge this gap. Through a multiple case study of four companies, we
identified challenges and critical elements within the different phases
(pre-implementation, implementation and post-implementation) of
the ERP life cycle. To interpret our findings, we utilize a well-know
ERP life cycle model and critical success factors developed for larger
companies which are reported in former research literature. We
discuss if these models are relevant for SMEs and suggest additional
critical elements identified in this study to make a framework more
adapted to the SME context.
Abstract: The importance of our country-s communication
system is noticeable when a disaster occurs. The communication
system in our country includes wired and wireless telephone
networks, radio, satellite system and more increasingly internet. Even
though our communication system is most extensive and dependable,
extreme conditions can put a strain on them. Interoperability between
heterogeneous wireless networks can be used to provide efficient
communication for emergency first response. IEEE 802.21 specifies
Media Independent Handover (MIH) services to enhance the mobile
user experience by optimizing handovers between heterogeneous
access networks. This paper presents an algorithm to improve
congestion control in MIH framework. It is analytically shown that
by including time factor in network selection we can optimize
congestion in the network.
Abstract: This paper deals with automatic sentence modality
recognition in French. In this work, only prosodic features are
considered. The sentences are recognized according to the three
following modalities: declarative, interrogative and exclamatory
sentences. This information will be used to animate a talking head for
deaf and hearing-impaired children. We first statistically study a real
radio corpus in order to assess the feasibility of the automatic
modeling of sentence types. Then, we test two sets of prosodic
features as well as two different classifiers and their combination. We
further focus our attention on questions recognition, as this modality
is certainly the most important one for the target application.
Abstract: Vickers indentation is used to measure the hardness
of materials. In this study, numerical simulation of Vickers
indentation experiment was performed for Diamond like Carbon
(DLC) coated materials. DLC coatings were deposited on stainless
steel 304 substrates with Chromium buffer layer using RF Magnetron
and T-shape Filtered Cathodic Vacuum Arc Dual system The
objective of this research is to understand the elastic plastic
properties, stress strain distribution, ring and lateral crack growth and
propagation, penetration depth of indenter and delamination of
coating from substrate with effect of buffer layer thickness. The
effect of Poisson-s ratio of DLC coating was also analyzed. Indenter
penetration is more in coated materials with thin buffer layer as
compared to thicker one, under same conditions. Similarly, the
specimens with thinner buffer layer failed quickly due to high
residual stress as compared to the coated materials with reasonable
thickness of 200nm buffer layer. The simulation results suggested the
optimized thickness of 200 nm among the prepared specimens for
durable and long service.
Abstract: This article is focused on the calculation of heat
radiation intensity and its optimization on an aluminum mould
surface. The inside of the mould is sprinkled with a special powder
and its outside is heated by infra heaters located above the mould
surface, up to a temperature of 250°C. By this way artificial leathers
in the car industry are produced (e. g. the artificial leather on a car
dashboard). A mathematical model of heat radiation of infra heaters
on a mould surface is described in this paper. This model allows us to
calculate a heat-intensity radiation on the mould surface for the
concrete location of infra heaters above the mould surface. It is
necessary to ensure approximately the same heat intensity radiation
on the mould surface by finding a suitable location for the infra
heaters, and in this way the same material structure and color of
artificial leather. In the model we have used a genetic algorithm to
optimize the radiation intensity on the mould surface. Experimental
measured values for the heat radiation intensity by a sensor in the
surroundings of an infra heater are used for the calculation
procedures. A computational procedure was programmed in language
Matlab.
Abstract: Artificial Neural Network (ANN)s can be modeled for
High Energy Particle analysis with special emphasis on shower core
location. The work describes the use of an ANN based system which
has been configured to predict locations of cores of showers in the
range 1010.5 to 1020.5 eV. The system receives density values as
inputs and generates coordinates of shower events recorded for values
captured by 20 core positions and 80 detectors in an area of 100
meters. Twenty ANNs are trained for the purpose and the positions
of shower events optimized by using cooperative ANN learning. The
results derived with variations of input upto 50% show success rates
in the range of 90s.
Abstract: This paper aims to study at the use of local knowledge
to develop community self-protection in flood prone residential area,
Ayutthaya Island has been chosen as a case study. This study tries to
examine the strength of local knowledge which is able to develop
community self-protection and cope with flood disaster. In-depth, this
paper focuses on the influence of social network on knowledge
transfer. After conducted the research, authors reviewed the strength
of local knowledge and also mentioned the obstacles of community to
use and also transfer local knowledge. Moreover, the result of the
study revealed that local knowledge is not always transferred by the
strongest-tie social network (family or kinship) as we used to believe.
Surprisingly, local knowledge could be also transferred by the
weaker-tie social network (teacher/ monk) with the better
effectiveness in some knowledge.
Abstract: The aim of this study is to discover secondary school students’ perceptions related to information technologies and the connections between concepts in their cognitive structures. A word association test consisting of six concepts related to information technologies is used to collect data from 244 secondary school students. Concept maps that present students’ cognitive structures are drawn with the help of frequency data. Data are analyzed and interpreted according to the connections obtained as a result of the concept maps. It is determined students associate most with these concepts—computer, Internet, and communication of the given concepts, and associate least with these concepts—computer-assisted education and information technologies. These results show the concepts, Internet, communication, and computer, are an important part of students’ cognitive structures. In addition, students mostly answer computer, phone, game, Internet and Facebook as the key concepts. These answers show students regard information technologies as a means for entertainment and free time activity, not as a means for education.
Abstract: Distributed Power generation has gained a lot of
attention in recent times due to constraints associated with
conventional power generation and new advancements in DG
technologies .The need to operate the power system economically
and with optimum levels of reliability has further led to an increase
in interest in Distributed Generation. However it is important to place
Distributed Generator on an optimum location so that the purpose of
loss minimization and voltage regulation is dully served on the
feeder. This paper investigates the impact of DG units installation on
electric losses, reliability and voltage profile of distribution networks.
In this paper, our aim would be to find optimal distributed
generation allocation for loss reduction subjected to constraint of
voltage regulation in distribution network. The system is further
analyzed for increased levels of Reliability. Distributed Generator
offers the additional advantage of increase in reliability levels as
suggested by the improvements in various reliability indices such as
SAIDI, CAIDI and AENS. Comparative studies are performed and
related results are addressed. An analytical technique is used in order
to find the optimal location of Distributed Generator. The suggested
technique is programmed under MATLAB software. The results
clearly indicate that DG can reduce the electrical line loss while
simultaneously improving the reliability of the system.
Abstract: Saccharomyces cerevisiae (baker-s yeast) can exhibit
sustained oscillations during the operation in a continuous bioreactor
that adversely affects its stability and productivity. Because of
heterogeneous nature of cell populations, the cell population balance
models can be used to capture the dynamic behavior of such cultures.
In this paper an unstructured, segregated model is used which is
based on population balance equation(PBE) and then in order to
simulation, the 4th order Rung-Kutta is used for time dimension and
three methods, finite difference, orthogonal collocation on finite
elements and Galerkin finite element are used for discretization of the
cell mass domain. The results indicate that the orthogonal collocation
on finite element not only is able to predict the oscillating behavior of
the cell culture but also needs much little time for calculations.
Therefore this method is preferred in comparison with other methods.
In the next step two controllers, a globally linearizing control (GLC)
and a conventional proportional-integral (PI) controller are designed
for controlling the total cell mass per unit volume, and performances
of these controllers are compared through simulation. The results
show that although the PI controller has simpler structure, the GLC
has better performance.
Abstract: The power transformer is the most expensive, indispensable and arguably the most important equipment item in a power system Insulation failure in transformers can cause long term interruption to supply and loss of revenue and the condition assessment of the insulation is thus an important maintenance procedure. Oil-impregnated transformer insulation consists of mainly organic materials including mineral oil and cellulose-base paper and pressboard. The operating life of cellulose-based insulation, as with most organic insulation, depends heavily on its operating temperature rise above ambient. This paper reports results of a laboratory-based experimental investigation of partial discharge (PD) activity at high temperature in oil-impregnated insulation. The experiments reported here are part an on-going programme aimed at investigating the way in which insulation deterioration can be monitored and quantified by use of partial discharge diagnostics. Partial discharge patterns were recorded and analysed during increasing and decreasing phases of the temperature. The effect of ageing of the insulation on the PD patterns in oil and oil-impregnated insulation are also considered.
Abstract: To maximise furnace production it-s necessary to
optimise furnace control, with the objectives of achieving maximum
power input into the melting process, minimum network distortion
and power-off time, without compromise on quality and safety. This
can be achieved with on the one hand by an appropriate electrode
control and on the other hand by a minimum of AC transformer
switching.
Electrical arc is a stochastic process; witch is the principal cause
of power quality problems, including voltages dips, harmonic
distortion, unbalance loads and flicker. So it is difficult to make an
appropriate model for an Electrical Arc Furnace (EAF). The factors
that effect EAF operation are the melting or refining materials,
melting stage, electrode position (arc length), electrode arm control
and short circuit power of the feeder. So arc voltages, current and
power are defined as a nonlinear function of the arc length. In this
article we propose our own empirical function of the EAF and model,
for the mean stages of the melting process, thanks to the
measurements in the steel factory.