Abstract: It is well-known that in wireless local area networks,
authenticating nodes by their MAC addresses is not secure since it is
very easy for an attacker to learn one of the authorized addresses and
change his MAC address accordingly. In this paper, in order to
prevent MAC address spoofing attacks, we propose to use
dynamically changing MAC addresses and make each address usable
for only one session. The scheme we propose does not require any
change in 802.11 protocols and incurs only a small performance
overhead. One of the nice features of our new scheme is that no third
party can link different communication sessions of the same user by
monitoring MAC addresses therefore our scheme is preferable also
with respect to user privacy.
Abstract: This study aims to assess the potential of solar energy technology for improving access to water and hence the livelihood strategies of rural communities in Baja California Sur, Mexico. It focuses on livestock ranches and photovoltaic water-pumptechnology as well as other water extraction methods. The methodology used are the Sustainable Livelihoods and the Appropriate Technology approaches. A household survey was applied in June of 2006 to 32 ranches in the municipality, of which 22 used PV pumps; and semi-structured interviews were conducted. Findings indicate that solar pumps have in fact helped people improve their quality of life by allowing them to pursue a different livelihood strategy and that improved access to water -not necessarily as more water but as less effort to extract and collect it- does not automatically imply overexploitation of the resource; consumption is based on basic needs as well as on storage and pumping capacity. Justification for such systems lies in the avoidance of logistical problems associated to fossil fuels, PV pumps proved to be the most beneficial when substituting gasoline or diesel equipment but of dubious advantage if intended to replace wind or gravity systems. Solar water pumping technology-s main obstacle to dissemination are high investment and repairs costs and it is therefore not suitable for all cases even when insolation rates and water availability are adequate. In cases where affordability is not an obstacle it has become an important asset that contributes –by means of reduced expenses, less effort and saved time- to the improvement of livestock, the main livelihood provider for these ranches.
Abstract: In recent years there has been a continuous increase of
axle loads, tonnage, train speed and train length which has increased
both the productivity in the rail sector and the risk of rail breaks and
derailments. On the other hand, the environmental requirements (e.g.
noise reduction) for railway operations will become tighter in the
future. In our research we developed a new composite material which
does not change braking properties, is capable of taking extremely
high pressure loads, reduces noise and is environmentally friendly.
Part of our research was also the development of technology which
will be able to apply this material to the rail. The result of our
research was the system which reduces the wear out significantly and
almost completely eliminates the squealing noise at the same time,
and by using only one special material.
Abstract: This paper discusses a new heavy tailed distribution based data hiding into discrete cosine transform (DCT) coefficients of image, which provides statistical security as well as robustness against steganalysis attacks. Unlike other data hiding algorithms, the proposed technique does not introduce much effect in the stegoimage-s DCT coefficient probability plots, thus making the presence of hidden data statistically undetectable. In addition the proposed method does not compromise on hiding capacity. When compared to the generic block DCT based data-hiding scheme, our method found more robust against a variety of image manipulating attacks such as filtering, blurring, JPEG compression etc.
Abstract: The aim of this work is to present a multi-objective optimization method to find maximum efficiency kinematics for a flapping wing unmanned aerial vehicle. We restrained our study to rectangular wings with the same profile along the span and to harmonic dihedral motion. It is assumed that the birdlike aerial vehicle (whose span and surface area were fixed respectively to 1m and 0.15m2) is in horizontal mechanically balanced motion at fixed speed. We used two flight physics models to describe the vehicle aerodynamic performances, namely DeLaurier-s model, which has been used in many studies dealing with flapping wings, and the model proposed by Dae-Kwan et al. Then, a constrained multi-objective optimization of the propulsive efficiency is performed using a recent evolutionary multi-objective algorithm called є-MOEA. Firstly, we show that feasible solutions (i.e. solutions that fulfil the imposed constraints) can be obtained using Dae-Kwan et al.-s model. Secondly, we highlight that a single objective optimization approach (weighted sum method for example) can also give optimal solutions as good as the multi-objective one which nevertheless offers the advantage of directly generating the set of the best trade-offs. Finally, we show that the DeLaurier-s model does not yield feasible solutions.
Abstract: The African Great Lakes Region refers to the zone
around lakes Victoria, Tanganyika, Albert, Edward, Kivu, and
Malawi. The main source of electricity in this region is hydropower
whose systems are generally characterized by relatively weak,
isolated power schemes, poor maintenance and technical deficiencies
with limited electricity infrastructures. Most of the hydro sources are
rain fed, and as such there is normally a deficiency of water during
the dry seasons and extended droughts. In such calamities fossil fuels
sources, in particular petroleum products and natural gas, are
normally used to rescue the situation but apart from them being nonrenewable,
they also release huge amount of green house gases to our
environment which in turn accelerates the global warming that has at
present reached an amazing stage. Wind power is ample, renewable,
widely distributed, clean, and free energy source that does not
consume or pollute water. Wind generated electricity is one of the
most practical and commercially viable option for grid quality and
utility scale electricity production. However, the main shortcoming
associated with electric wind power generation is fluctuation in its
output both in space and time. Before making a decision to establish
a wind park at a site, the wind speed features there should therefore
be known thoroughly as well as local demand or transmission
capacity. The main objective of this paper is to utilise monthly
average wind speed data collected from one prospective site within
the African Great Lakes Region to demonstrate that the available
wind power there is high enough to generate electricity. The mean
monthly values were calculated from records gathered on hourly
basis for a period of 5 years (2001 to 2005) from a site in Tanzania.
The documentations that were collected at a height of 2 m were
projected to a height of 50 m which is the standard hub height of
wind turbines. The overall monthly average wind speed was found to
be 12.11 m/s whereas June to November was established to be the
windy season as the wind speed during the session is above the
overall monthly wind speed. The available wind power density
corresponding to the overall mean monthly wind speed was evaluated
to be 1072 W/m2, a potential that is worthwhile harvesting for the
purpose of electric generation.
Abstract: Diesel Engines emit complex mixtures of inorganic
and organic compounds in the form of both solid and vapour phase
particles. Most of the particulates released are ultrafine nanoparticles
which are detrimental to human health and can easily enter the body
by respiration. The emissions standards on particulate matter release
from diesel engines are constantly upgraded within the European
Union and with future regulations based on the particles numbers
released instead of merely mass, the need for effective aftertreatment
devices will increase. Standard particulate filters in the form of wall
flow filters can have problems with high soot accumulation,
producing a large exhaust backpressure. A potential solution would
be to combine the standard filter with a flow through filter to reduce
the load on the wall flow filter. In this paper soot particle trapping has
been simulated in different continuous flow filters of monolithic
structure including the use of promoters, at laminar flow conditions.
An Euler Lagrange model, the discrete phase model in Ansys used
with user defined functions for forces acting on particles. A method
to quickly screen trapping of 5 nm and 10 nm particles in different
catalysts designs with tracers was also developed.
Simulations of square duct monoliths with promoters show that the
strength of the vortices produced are not enough to give a high
amount of particle deposition on the catalyst walls. The smallest
particles in the simulations, 5 and 10 nm particles were trapped to a
higher extent, than larger particles up to 1000 nm, in all studied
geometries with the predominant deposition mechanism being
Brownian diffusion. The comparison of the different filters designed
with a wall flow filter does show that the options for altering a design
of a flow through filter, without imposing a too large pressure drop
penalty are good.
Abstract: In this study, the performance of a high-frequency arc
welding machine including a two-switch inverter is analyzed. The
control of the system is achieved using two different control
techniques i- fuzzy logic control (FLC) ii- state space averaging
based sliding control. Fuzzy logic control does not need accurate
mathematical model of a plant and can be used in nonlinear
applications. The second method needs the mathematical model of
the system. In this method the state space equations of the system are
derived for two different “on" and “off" states of the switches. The
derived state equations are combined with the sliding control rule
considering the duty-cycle of the converter. The performance of the
system is analyzed by simulating the system using SIMULINK tool
box of MATLAB. The simulation results show that fuzzy logic
controller is more robust and less sensitive to parameter variations.
Abstract: Midpoint filter is quite effective in recovering the
images confounded by the short-tailed (uniform) noise. It, however,
performs poorly in the presence of additive long-tailed (impulse)
noise and it does not preserve the edge structures of the image
signals. Median smoother discards outliers (impulses) effectively, but
it fails to provide adequate smoothing for images corrupted with nonimpulse
noise. In this paper, two nonlinear techniques for image
filtering, namely, New Filter I and New Filter II are proposed based
on a nonlinear high-pass filter algorithm. New Filter I is constructed
using a midpoint filter, a highpass filter and a combiner. It suppresses
uniform noise quite well. New Filter II is configured using an alpha
trimmed midpoint filter, a median smoother of window size 3x3, the
high pass filter and the combiner. It is robust against impulse noise
and attenuates uniform noise satisfactorily. Both the filters are shown
to exhibit good response at the image boundaries (edges). The
proposed filters are evaluated for their performance on a test image
and the results obtained are included.
Abstract: Textile structures are engineered and fabricated to
meet worldwide structural applications. Nevertheless, research
varying textile structure on natural fibre as composite reinforcement
was found to be very limited. Most of the research is focusing on
short fibre and random discontinuous orientation of the reinforcement
structure. Realizing that natural fibre (NF) composite had been
widely developed to be used as synthetic fibre composite
replacement, this research attempted to examine the influence of
woven and cross-ply laminated structure towards its mechanical
performances. Laminated natural fibre composites were developed
using hand lay-up and vacuum bagging technique. Impact and
flexural strength were investigated as a function of fibre type (coir
and kenaf) and reinforcement structure (imbalanced plain woven,
0°/90° cross-ply and +45°/-45° cross-ply). Multi-level full factorial
design of experiment (DOE) and analysis of variance (ANOVA) was
employed to impart data as to how fibre type and reinforcement
structure parameters affect the mechanical properties of the
composites. This systematic experimentation has led to determination
of significant factors that predominant influences the impact and
flexural properties of the textile composites. It was proven that both
fibre type and reinforcement structure demonstrated significant
difference results. Overall results indicated that coir composite and
woven structure exhibited better impact and flexural strength. Yet,
cross-ply composite structure demonstrated better fracture resistance.
Abstract: As is needless to say; a majority of accidents, which occur, are due to drunk driving. As such, there is no effective mechanism to prevent this. Here we have designed an integrated system for the same purpose. Alcohol content in the driver-s body is detected by means of an infrared breath analyzer placed at the steering wheel. An infrared cell directs infrared energy through the sample and any unabsorbed energy at the other side is detected. The higher the concentration of ethanol, the more infrared absorption occurs (in much the same way that a sunglass lens absorbs visible light, alcohol absorbs infrared light). Thus the alcohol level of the driver is continuously monitored and calibrated on a scale. When it exceeds a particular limit the fuel supply is cutoff. If the device is removed also, the fuel supply will be automatically cut off or an alarm is sounded depending upon the requirement. This does not happen abruptly and special indicators are fixed at the back to avoid inconvenience to other drivers using the highway signals. Frame work for integration of sensors and control module in a scalable multi-agent system is provided .A SMS which contains the current GPS location of the vehicle is sent via a GSM module to the police control room to alert the police. The system is foolproof and the driver cannot tamper with it easily. Thus it provides an effective and cost effective solution for the problem of drunk driving in vehicles.
Abstract: A serious problem on the WWW is finding reliable
information. Not everything found on the Web is true and the
Semantic Web does not change that in any way. The problem will be
even more crucial for the Semantic Web, where agents will be
integrating and using information from multiple sources. Thus, if an
incorrect premise is used due to a single faulty source, then any
conclusions drawn may be in error. Thus, statements published on
the Semantic Web have to be seen as claims rather than as facts, and
there should be a way to decide which among many possibly
inconsistent sources is most reliable. In this work, we propose a trust
model for the Semantic Web. The proposed model is inspired by the
use trust in human society. Trust is a type of social knowledge and
encodes evaluations about which agents can be taken as reliable
sources of information or services. Our proposed model allows
agents to decide which among different sources of information to
trust and thus act rationally on the semantic web.
Abstract: Most of the Question Answering systems
composed of three main modules: question processing,
document processing and answer processing. Question
processing module plays an important role in QA systems. If
this module doesn't work properly, it will make problems for
other sections. Moreover answer processing module is an
emerging topic in Question Answering, where these systems
are often required to rank and validate candidate answers.
These techniques aiming at finding short and precise answers
are often based on the semantic classification.
This paper discussed about a new model for question
answering which improved two main modules, question
processing and answer processing.
There are two important components which are the bases
of the question processing. First component is question
classification that specifies types of question and answer.
Second one is reformulation which converts the user's
question into an understandable question by QA system in a
specific domain. Answer processing module, consists of
candidate answer filtering, candidate answer ordering
components and also it has a validation section for interacting
with user. This module makes it more suitable to find exact
answer. In this paper we have described question and answer
processing modules with modeling, implementing and
evaluating the system. System implemented in two versions.
Results show that 'Version No.1' gave correct answer to 70%
of questions (30 correct answers to 50 asked questions) and
'version No.2' gave correct answers to 94% of questions (47
correct answers to 50 asked questions).
Abstract: A lot of research has been done in the past decade in the field of audio content analysis for extracting various information from audio signal. One such significant information is the "perceived mood" or the "emotions" related to a music or audio clip. This information is extremely useful in applications like creating or adapting the play-list based on the mood of the listener. This information could also be helpful in better classification of the music database. In this paper we have presented a method to classify music not just based on the meta-data of the audio clip but also include the "mood" factor to help improve the music classification. We propose an automated and efficient way of classifying music samples based on the mood detection from the audio data. We in particular try to classify the music based on mood for Indian bollywood music. The proposed method tries to address the following problem statement: Genre information (usually part of the audio meta-data) alone does not help in better music classification. For example the acoustic version of the song "nothing else matters by Metallica" can be classified as melody music and thereby a person in relaxing or chill out mood might want to listen to this track. But more often than not this track is associated with metal / heavy rock genre and if a listener classified his play-list based on the genre information alone for his current mood, the user shall miss out on listening to this track. Currently methods exist to detect mood in western or similar kind of music. Our paper tries to solve the issue for Indian bollywood music from an Indian cultural context
Abstract: Depression is a serious mental health problem that
affects people of all ages, including children and adolescents. Studies
showed that female gender is one of the risk factors may influence
the development of depression in adolescents. However, some of the
studies from Turkey suggested that gender does not lead to any
significant difference in the youth depression level. Therefore, the
presented study investigated whether girls differ from boys in respect
of depression. The association between genders and test scores for
the adolescents in a population of primary and secondary school
students was also evaluated. The study was consisting of 254
adolescents (122 boys and 132 girls) with a mean age of 13.86±1.43
(Mean±SD) ranging from 12-16 years. Psychological assessment was
performed using Children-s Depression Inventory (CDI). Chi-square
and Student-s t-test statistics were employed to analyze the data. The
mean of the CDI scores of the girls were higher than boys- CDI
scores (t = -4.580, p = 0.001). Higher ratio appeared for the girls
when they compared with boy group-s depression levels using a CDI
cut-off point of 19 (p = 0.001, Odds Ratio = 2,603). The findings of
the present study suggested that adolescent girls have high level of
depression than adolescent boys aged between 12-16 years in
Turkey. Although some studies reported that there is no any
differences depression level between adolescent boys and girls in
Turkey, result of the present study showed that adolescent girls have
high level of depression than adolescent boys in Turkey.
Abstract: The story of Alibaba demonstrates a credible example of how a small start-up company can eventually make it big in the global economy through the Internet. This case study does not attempt to present Alibaba as a perfect formula; rather, it discusses the strategies carried out by the firm and, in the process, culls out the important lessons that can guide start-ups and aspiring entrepreneurs in the complex world of online trading. Similar to the interesting and exotic Asian cuisine that continuously evolves from the diversity of Asia-s people and their unique culture and personality, Alibaba has successfully transformed itself over the years, adapting to the changes in and demands of online businessto- business (B2B) commerce.
Abstract: In order to enhance the contrast in the regions where the pixels have similar intensities, this paper presents a new histogram equalization scheme. Conventional global equalization schemes over-equalizes these regions so that too bright or dark pixels are resulted and local equalization schemes produce unexpected discontinuities at the boundaries of the blocks. The proposed algorithm segments the original histogram into sub-histograms with reference to brightness level and equalizes each sub-histogram with the limited extents of equalization considering its mean and variance. The final image is determined as the weighted sum of the equalized images obtained by using the sub-histogram equalizations. By limiting the maximum and minimum ranges of equalization operations on individual sub-histograms, the over-equalization effect is eliminated. Also the result image does not miss feature information in low density histogram region since the remaining these area is applied separating equalization. This paper includes how to determine the segmentation points in the histogram. The proposed algorithm has been tested with more than 100 images having various contrasts in the images and the results are compared to the conventional approaches to show its superiority.
Abstract: This paper addresses the problem of determining the current 3D location of a moving object and robustly tracking it from a sequence of camera images. The approach presented here uses a particle filter and does not perform any explicit triangulation. Only the color of the object to be tracked is required, but not any precisemotion model. The observation model we have developed avoids the color filtering of the entire image. That and the Monte Carlotechniques inside the particle filter provide real time performance.Experiments with two real cameras are presented and lessons learned are commented. The approach scales easily to more than two cameras and new sensor cues.
Abstract: Rounding of coefficients is a common practice in
hardware implementation of digital filters. Where some coefficients
are very close to zero or one, as assumed in this paper, this rounding
action also leads to some computation reduction. Furthermore, if the
discarded coefficient is of high order, a reduced order filter is
obtained, otherwise the order does not change but computation is
reduced. In this paper, the Least Squares approximation to rounded
(or discarded) coefficient FIR filter is investigated. The result also
succinctly extended to general type of FIR filters.
Abstract: Neural networks are well known for their ability to
model non linear functions, but as statistical methods usually does,
they use a no parametric approach thus, a priori knowledge is not
obvious to be taken into account no more than the a posteriori
knowledge. In order to deal with these problematics, an original way
to encode the knowledge inside the architecture is proposed. This
method is applied to the problem of the evapotranspiration inside
karstic aquifer which is a problem of huge utility in order to deal
with water resource.