Abstract: The paper presents a numerical investigation on the
rapid gas decompression in pure nitrogen which is made by using the
one-dimensional (1D) and three-dimensional (3D) mathematical
models of transient compressible non-isothermal fluid flow in pipes.
A 1D transient mathematical model of compressible thermal multicomponent
fluid mixture flow in pipes is presented. The set of the
mass, momentum and enthalpy conservation equations for gas phase
is solved in the model. Thermo-physical properties of multicomponent
gas mixture are calculated by solving the Equation of
State (EOS) model. The Soave-Redlich-Kwong (SRK-EOS) model is
chosen. This model is successfully validated on the experimental data
[1] and shows a good agreement with measurements. A 3D transient
mathematical model of compressible thermal single-component gas
flow in pipes, which is built by using the CFD Fluent code (ANSYS),
is presented in the paper. The set of unsteady Reynolds-averaged
conservation equations for gas phase is solved. Thermo-physical
properties of single-component gas are calculated by solving the Real
Gas Equation of State (EOS) model. The simplest case of gas
decompression in pure nitrogen is simulated using both 1D and 3D
models. The ability of both models to simulate the process of rapid
decompression with a high order of agreement with each other is
tested. Both, 1D and 3D numerical results show a good agreement
between each other. The numerical investigation shows that 3D CFD
model is very helpful in order to validate 1D simulation results if the
experimental data is absent or limited.
Abstract: Digital signature is a useful primitive to attain the integrity and authenticity in various wire or wireless communications. Proxy signature is one type of the digital signatures. It helps the proxy signer to sign messages on behalf of the original signer. It is very useful when the original signer (e.g. the president of a company) is not available to sign a specific document. If the original signer can not forge valid proxy signatures through impersonating the proxy signer, it will be robust in a virtual environment; thus the original signer can not shift any illegal action initiated by herself to the proxy signer. In this paper, we propose a new proxy signature scheme. The new scheme can prevent the original signer from impersonating the proxy signer to sign messages. The proposed scheme is based on the regular ElGamal signature. In addition, the fair privacy of the proxy signer is maintained. That means, the privacy of the proxy signer is preserved; and the privacy can be revealed when it is necessary.
Abstract: Interpolated contour maps drawn for aluminum,
copper and molybdenum in downstream monitoring boreholes of
water dam in Miduk Copper Complex and the values of pH, redox
potential (Eh) and distance from water dam indicate different trends
of variation and behavior of these three elements in downward
groundwater resources. As these maps exhibit, aluminum is dominant
in the most alkaline (pH = 9-11) borehole (MB5) to water dam. The
highest concentration of molybdenum is found in the nearest
borehole (MB6) to water dam. Main concentration of copper is
observed in the most oxidized borehole (MB3 with Eh=293.2mV).
The spatial difference among sampling stations can be attributed to
the existence of faults and diaclases in the geologic structure of
Miduk region which causes the groundwater sampling sites to be
impressed by different contamination sources (toe seepage and upper
seepage water originated from different zones of tailings dump).
Abstract: In this paper we present a novel error model for
packet loss and subsequent error description. The proposed model
simulates the error performance of wireless communication link. The
model is designed as two independent Markov chains, where the first
one is used for packet generation and the second one generates
correctly and incorrectly transmitted bits for received packets from
the first chain. The statistical analyses of real communication on the
wireless link are used for determination of model-s parameters. Using
the obtained parameters and the implementation of the generator, we
collected generated traffic. The obtained results generated by
proposed model are compared with the real data collection.
Abstract: In a 10-week (May – August, 2008) Phase I trial, 840, 1+ rainbow trout, Oncorhynchus mykiss, received a commercial oral immunomodulator, Fin Immune™, at four different dosages (0, 10, 20 and 30 mg g-1) to evaluate immune response and growth. The overall objective of was to determine an optimal dosage of this product for rainbow trout that provides enhanced immunity with maximal growth and health. Biweekly blood samples were taken from 10 randomly selected fish in each tank (30 samples per treatment) to evaluate the duration of enhanced immunity conferred by Fin-Immune™. The immunological assessment included serum white blood cell (lymphocyte, neutrophil) densities and blood hematocrit (packed cell volume %). Of these three variables, only lymphocyte density increased significantly among trout fed Fin- Immune™ at 20 and 30 mg g-1 which peaked at week 6. At week 7, all trout were switched to regular feed (lacking Fin-Immune™) and by week 10, lymphocyte levels decreased among all levels but were still greater than at week 0. There was growth impairment at the highest dose of Fin-Immune™ tested (30 mg g-1) which can be associated with a physiological compensatory mechanism due to a dose-specific threshold level. Thus, our main objective of this Phase I study was achieved, the 20 mg g-1 dose of Fin-Immune™ should be the most efficacious (of those we tested) to use for a Phase II disease challenge trial.
Abstract: In view of growing competition in the service sector,
services are as much in need of modeling, analysis and improvement
as business or working processes. Graphical process models are
important means to capture process-related know-how for an
effective management of the service process. In this contribution, a
human performance analysis of process model development paying
special attention to model development time and the working method
was conducted. It was found that modelers with higher application
experience need significantly less time for mental activities than
modelers with lower application experience, spend more time on
labeling graphical elements, and achieved higher process model
quality in terms of activity label quality.
Abstract: This paper focuses on systematic analysis and
controller design of the two-inertia STABILIZATION system,
considering the angular motion on a base body. This approach is
essential to the stabilization system to aim at a target under three or six
degrees of freedom base motion. Four controllers, such as
conventional PDF(Pseudo-Derivative Feedback) controller with
motor speed feedback, PDF controller with load speed feedback,
modified PDF controller with motor-load speed feedback and
feedforward controller added to modified PDF controller, are
suggested to improve reference tracking and disturbance rejection
performance. Characteristics and performance of each controller are
analyzed and validated by simulation in the case of the modified PDF
controller with and without a feedforward controller.
Abstract: Estimates of temperature values at a specific time of day, from daytime and daily profiles, are needed for a number of environmental, ecological, agricultural and technical applications, ranging from natural hazards assessments, crop growth forecasting to design of solar energy systems. The scope of this research is to investigate the efficiency of data mining techniques in estimating minimum, maximum and mean temperature values. For this reason, a number of experiments have been conducted with well-known regression algorithms using temperature data from the city of Patras in Greece. The performance of these algorithms has been evaluated using standard statistical indicators, such as Correlation Coefficient, Root Mean Squared Error, etc.
Abstract: In the past, there were many bridge-s collapses due to
lack of bridge structural capacity information. Most of concrete
bridge health was relied on information from visual inspection, which
sometime was inadequate. This study was conducted in order to
investigate relationship between bridge structural condition and
bridge visual condition. This study was a part of a big project
conducted at Department of Highways of Thailand. In this study, 31
bridges including slab-type bridges, plank-girder bridges, prestressed
box-beam bridges, prestressed I-girder bridges and prestressed multibeam
bridges were selected for visual inspection and load test. It was
found a positive correlation between bridge appearance and bridge-s
load carrying capacity. However, statistical characteristic revealed
low correlation between them.
Abstract: The concerns of education and practice of architecture
do not necessarily overlap. Indeed the gap between them could be
seen increasingly and less frequently bridged. We suggest that
changing in architecture education and clarifying the relationship
between these two can help to find and address the opportunities and
unique positions to bridge this gulf.
Abstract: A novel feature selection strategy to improve the recognition accuracy on the faces that are affected due to nonuniform illumination, partial occlusions and varying expressions is proposed in this paper. This technique is applicable especially in scenarios where the possibility of obtaining a reliable intra-class probability distribution is minimal due to fewer numbers of training samples. Phase congruency features in an image are defined as the points where the Fourier components of that image are maximally inphase. These features are invariant to brightness and contrast of the image under consideration. This property allows to achieve the goal of lighting invariant face recognition. Phase congruency maps of the training samples are generated and a novel modular feature selection strategy is implemented. Smaller sub regions from a predefined neighborhood within the phase congruency images of the training samples are merged to obtain a large set of features. These features are arranged in the order of increasing distance between the sub regions involved in merging. The assumption behind the proposed implementation of the region merging and arrangement strategy is that, local dependencies among the pixels are more important than global dependencies. The obtained feature sets are then arranged in the decreasing order of discriminating capability using a criterion function, which is the ratio of the between class variance to the within class variance of the sample set, in the PCA domain. The results indicate high improvement in the classification performance compared to baseline algorithms.
Abstract: In Blind Source Separation (BSS) processing, taking
advantage of scaling factor indetermination and based on the floatingpoint
representation, we propose a scaling technique applied to the
separation matrix, to avoid the saturation or the weakness in the
recovered source signals. This technique performs an Automatic Gain
Control (AGC) in an on-line BSS environment. We demonstrate
the effectiveness of this technique by using the implementation of
a division free BSS algorithm with two input, two output. This
technique is computationally cheaper and efficient for a hardware
implementation.
Abstract: There has been considerable growth in the issue of
food & beverage safety in Thailand. This is important because the
level of satisfaction in food & beverage safety has impacts on travel
decision made by foreign tourists. Therefore, this paper was aimed to
test if there is any significant gender effect in the level of satisfaction
of food & beverage safety made by foreign tourists in Thailand. In
addition, this paper utilized the Chi Square test of independent to test
if there was an association between gender and sickness because of
food and if there was an association between gender and the
perception of food safety standard. During January to June, 2012, a
total of 400 foreign tourist respondents, 200 male as well as 200
female foreign tourists, were interviewed at the departure lounge at
Suvarnabhumi airport, Thailand. The findings revealed the
astonishing result that there was no significant effect of gender. Also,
there was no significant difference in the association between gender
and being sick because of food as well as the association between
gender and the perception on the standard of food safety during their
trip in Thailand.
Abstract: This study attempts to validate the consumer-oriented
criteria list, developed by Wang et al. (2010), for selecting online
travel shopping sites. Based on a sample of 985 respondents,
confirmatory factor analysis was employed to test the factor structure
and assess the reliability and validity of the list. The results support the
list developed by Wang et al. (2010) and claim the list can be further
used to analyze, explain, and understand consumer behaviors about
online travel shopping.
Abstract: Our goal is to effectively increase the number of boats in the river during a six month period. The main factors of determining the number of boats are duration and “select the priority trip". In the microcosmic simulation model, the best result is 4 to 24 nights with DSCF, and the number of boats is 812 with an increasing ratio of 9.0% related to the second best result. However, the number of boats is related to 31.6% less than the best one in 6 to 18 nights with FCFS. In the discrete duration model, we get from 6 to 18 nights, the numbers of boats have increased to 848 with an increase ratio of 29.7% than the best result in model I for the same time range. Moreover, from 4 to 24 nights, the numbers of boats have increase to 1194 with an increase ratio of 47.0% than the best result in model I for the same time range.
Abstract: We describe an effective method for image encryption
which employs magnitude and phase manipulation using carrier
images. Although it involves traditional methods like magnitude and
phase encryptions, the novelty of this work lies in deploying the
concept of carrier images for encryption purpose. To this end, a
carrier image is randomly chosen from a set of stored images. One
dimensional (1-D) discrete Fourier transform (DFT) is then carried
out on the original image to be encrypted along with the carrier
image. Row wise spectral addition and scaling is performed between
the magnitude spectra of the original and carrier images by randomly
selecting the rows. Similarly, row wise phase addition and scaling is
performed between the original and carrier images phase spectra by
randomly selecting the rows. The encrypted image obtained by these
two operations is further subjected to one more level of magnitude
and phase manipulation using another randomly chosen carrier image
by 1-D DFT along the columns. The resulting encrypted image is
found to be fully distorted, resulting in increasing the robustness
of the proposed work. Further, applying the reverse process at the
receiver, the decrypted image is found to be distortionless.
Abstract: Periodicities in the environmetric time series can be
idyllically assessed by utilizing periodic models. In this
communication fugitive emission of gases from open sewer channel
Lyari which follows periodic behaviour are approximated by
employing periodic autoregressive model of order p. The orders of
periodic model for each season are selected through the examination
of periodic partial autocorrelation or information criteria. The
parameters for the selected order of season are estimated individually
for each emitted air toxin. Subsequently, adequacies of fitted models
are established by examining the properties of the residual for each
season. These models are beneficial for schemer and administrative
bodies for the improvement of implemented policies to surmount
future environmental problems.
Abstract: P2P Networks are highly dynamic structures since
their nodes – peer users keep joining and leaving continuously. In the
paper, we study the effects of network change rates on query routing
efficiency. First we describe some background and an abstract system
model. The chosen routing technique makes use of cached metadata
from previous answer messages and also employs a mechanism for
broken path detection and metadata maintenance. Several metrics are
used to show that the protocol behaves quite well even with high rate
of node departures, but above a certain threshold it literally breaks
down and exhibits considerable efficiency degradation.
Abstract: Bio-electrical responses obtained from freshwater
sediments by employing microbial fuel cell (MFC) technology were
investigated in this experimental study. During the electricity
generation, organic matter in the sediment was microbially oxidized
under anaerobic conditions with an electrode serving as a terminal
electron acceptor. It was found that the sediment organic matter
(SOM) associated with electrochemically-active electrodes became
more humified, aromatic, and polydispersed, and had a higher average
molecular weight, together with the decrease in the quantity of SOM.
The alteration of characteristics of the SOM was analogous to that
commonly observed in the early stage of SOM diagenetic process (i.e.,
humification). These findings including an elevation of the sediment
redox potential present a possibility of the MFC technology as a new
soil/sediment remediation technique based on its potential benefits:
non-destructive electricity generation and bioremediation.
Abstract: Iris-based biometric authentication is gaining importance
in recent times. Iris biometric processing however, is a complex
process and computationally very expensive. In the overall processing
of iris biometric in an iris-based biometric authentication system,
feature processing is an important task. In feature processing, we extract
iris features, which are ultimately used in matching. Since there
is a large number of iris features and computational time increases
as the number of features increases, it is therefore a challenge to
develop an iris processing system with as few as possible number of
features and at the same time without compromising the correctness.
In this paper, we address this issue and present an approach to feature
extraction and feature matching process. We apply Daubechies D4
wavelet with 4 levels to extract features from iris images. These
features are encoded with 2 bits by quantizing into 4 quantization
levels. With our proposed approach it is possible to represent an
iris template with only 304 bits, whereas existing approaches require
as many as 1024 bits. In addition, we assign different weights to
different iris region to compare two iris templates which significantly
increases the accuracy. Further, we match the iris template based on
a weighted similarity measure. Experimental results on several iris
databases substantiate the efficacy of our approach.