Abstract: In this paper some procedures for building confidence intervals for the reliability in stress-strength models are discussed and empirically compared. The particular case of a bivariate normal setup is considered. The confidence intervals suggested are obtained employing approximations or asymptotic properties of maximum likelihood estimators. The coverage and the precision of these intervals are empirically checked through a simulation study. An application to real paired data is also provided.
Abstract: Evaluation of educational portals is an important
subject area that needs more attention from researchers. A university
that has an educational portal which is difficult to use and interact by
teachers or students or management staff can reduce the position and
reputation of the university. Therefore, it is important to have the
ability to make an evaluation of the quality of e-services the
university provide to improve them over time.
The present study evaluates the usability of the Information
Technology Faculty portal at University of Benghazi. Two evaluation
methods were used: a questionnaire-based method and an online
automated tool-based method. The first method was used to measure
the portal's external attributes of usability (Information, Content and
Organization of the portal, Navigation, Links and Accessibility,
Aesthetic and Visual Appeal, Performance and Effectiveness and
educational purpose) from users' perspectives, while the second
method was used to measure the portal's internal attributes of
usability (number and size of HTML files, number and size of images,
load time, HTML check errors, browsers compatibility problems,
number of bad and broken links), which cannot be perceived by the
users. The study showed that some of the usability aspects have been
found at the acceptable level of performance and quality, and some
others have been found otherwise. In general, it was concluded that
the usability of IT faculty educational portal generally acceptable.
Recommendations and suggestions to improve the weakness and
quality of the portal usability are presented in this study.
Abstract: The purpose of this research was to demonstrate
prevalence of post-exposure preventive measures (PEP) after needlestick
injuries and its relationship with locus of control beliefs in a
sample of medical students. In this cross-sectional study, 300 medical
students with history of having experienced needle stick injuries
(NSI) for at least once filled in a questionnaire to determine if they
perceived themselves to be responsible and effective in preventing
blood born infections after NSI. About 38% of students did not seek
any professional consult or PEP after NSI due to lack of enough time
or access, anxiety about tests results, belief in uselessness of followup
and not being able to change destiny. These 114 students were not
different from others regarding their scores on NSI specific scale of
locus of health control. Thus, the potentiality of NSI locus of control
beliefs in predicting PEP was not seen in this study.
Abstract: The purpose of this study is to determine the
circumstances affecting elementary school students in their family
and school lives and what kind of emotions children may feel
because of these circumstances. The study was carried out according
to the survey model. Four Turkish elementary schools provided 123
fourth grade students for participation in the study. The study-s data
were collected by using worksheets for the activity titled “Important
Days in Our Lives", which was part of the Elementary School Social
Sciences Course 4th Grade Education Program. Data analysis was
carried out according to the content analysis technique used in
qualitative research. The study detected that circumstances of their
family and school lives caused children to feel emotions such as
happiness, sadness, anger, fear and jealousy. The circumstances and
the emotions caused by these circumstances were analyzed according
to gender and interpreted by presenting them with their frequencies.
Abstract: A personal estimate of a health risk may not
correspond to a scientific assessment of the health risk. Hence, there
is a need to investigate perceived health risks in the public. In this
study, a young, educated and healthy group of people from a tertiary
institute were questioned about their health concerns. Ethics
clearance was obtained and data was collected by means of a
questionnaire. 362 students participated in the study. Tobacco use,
heavy alcohol drinking, illicit drugs, unsafe sex and potential
carcinogens were perceived to be the five greatest threats to health in
this cohort. On the other hand natural health products,
unemployment, unmet contraceptive needs, family violence and
homelessness were felt to be the least perceived health risks.
Nutrition-related health risks as well as health risks due to physical
inactivity and obesity were not perceived as major health threats.
Such a study of health perceptions may guide health promotion
campaigns.
Abstract: By the application of an improved back-propagation
neural network (BPNN), a model of current densities for a solid oxide
fuel cell (SOFC) with 10 layers is established in this study. To build
the learning data of BPNN, Taguchi orthogonal array is applied to
arrange the conditions of operating parameters, which totally 7 factors
act as the inputs of BPNN. Also, the average current densities
achieved by numerical method acts as the outputs of BPNN.
Comparing with the direct solution, the learning errors for all learning
data are smaller than 0.117%, and the predicting errors for 27
forecasting cases are less than 0.231%. The results show that the
presented model effectively builds a mathematical algorithm to predict
performance of a SOFC stack immediately in real time.
Also, the calculating algorithms are applied to proceed with the
optimization of the average current density for a SOFC stack. The
operating performance window of a SOFC stack is found to be
between 41137.11 and 53907.89. Furthermore, an inverse predicting
model of operating parameters of a SOFC stack is developed here by
the calculating algorithms of the improved BPNN, which is proved to
effectively predict operating parameters to achieve a desired
performance output of a SOFC stack.
Abstract: Despite the internet, which is one of the mass media
that has become quite common in recent years, the relationship of
Advertisement with Television and Cinema, which have always
drawn attention of researchers as basic media and where visual use is
in the foreground, have also become the subject of various studies.
Based on the assumption that the known fundamental effects of
advertisements on consumers are closely related to the creative
process of advertisements as well as the nature and characteristics of
the medium where they are used, these basic mass media (Television
and Cinema) and the consumer motivations of the advertisements
they broadcast have become a focus of study.
Given that the viewers of the mass media in question have shifted
from a passive position to a more active one especially in recent years
and approach contents of advertisements, as they do all contents, in a
more critical and “pitiless" manner, it is possible to say that
individuals make more use of advertisements than in the past and
combine their individual goals with the goals of the advertisements.
This study, which aims at finding out what the goals of these new
individual advertisement use are, how they are shaped by the distinct
characteristics of Television and Cinema, where visuality takes
precedence as basic mass media, and what kind of places they occupy
in the minds of consumers, has determined consumers- motivations
as: “Entertainment", “Escapism", “Play", “Monitoring/Discovery",
“Opposite Sex" and “Aspirations and Role Models".
This study intends to reveal the differences or similarities among
the needs and hence the gratifications of viewers who consume
advertisements on Television or at the Cinema, which are two basic
media where visuality is prioritized.
Abstract: Some of the polycyclic aromatic hydrocarbons (PAHs)
are the strongest known carcinogens compounds; the majority of
them are mostly produced by the incomplete combustion of fossil
fuels; Motor vehicles are a significant source of polycyclic aromatic
hydrocarbon (PAH) where diesel emission is one of the main sources
of such compounds available in the ambient air. There is a big
concern about the increasing concentration of PAHs in the
environment. Researchers are trying to explore optimal methods to
reduce those pollutants and improve the quality of air. Water blended
fuel is one of the possible approaches to reduce emission of PAHs
from the combustion of diesel in urban and domestic vehicles. In this
work a modeling study was conducted using CHEMKIN-PRO
software to simulate spray combustion at similar diesel engine
conditions. Surrogate fuel of (80 % n-heptane and 20 % toluene) was
used due to detailed kinetic and thermodynamic data needed for
modeling is available for this kind of fuel but not available for diesel.
An emulsified fuel with 3, 5, 8, 10 and 20 % water by volume is used
as an engine feed for this study. The modeling results show that water
has a significant effect on reducing engine soot and PAHs precursors
formation up to certain extent.
Abstract: Background: Blunt aortic trauma (BAT) includes
various morphological changes that occur during deceleration,
acceleration and/or body compression in traffic accidents. The
various forms of BAT, from limited laceration of the intima to
complete transection of the aorta, depends on the force acting on the
vessel wall and the tolerance of the aorta to injury. The force depends
on the change in velocity, the dynamics of the accident and of the
seating position in the car. Tolerance to aortic injury depends on the
anatomy, histological structure and pathomorphological alterations
due to aging or disease of the aortic wall.
An overview of the literature and medical documentation reveals
that different terms are used to describe certain forms of BAT, which
can lead to misinterpretation of findings or diagnoses. We therefore,
propose a classification that would enable uniform systematic
screening of all forms of BAT. We have classified BAT into three
morphologycal types: TYPE I (intramural), TYPE II (transmural) and
TYPE III (multiple) aortic ruptures with appropriate subtypes.
Methods: All car accident casualties examined at the Institute of
Forensic Medicine from 2001 to 2009 were included in this
retrospective study. Autopsy reports were used to determine the
occurrence of each morphological type of BAT in deceased drivers,
front seat passengers and other passengers in cars and to define the
morphology of BAT in relation to the accident dynamics and the age
of the fatalities.
Results: A total of 391 fatalities in car accidents were included in
the study. TYPE I, TYPE II and TYPE III BAT were observed in
10,9%, 55,6% and 33,5%, respectively. The incidence of BAT in
drivers, front seat and other passengers was 36,7%, 43,1% and
28,6%, respectively. In frontal collisions, the incidence of BAT was
32,7%, in lateral collisions 54,2%, and in other traffic accidents
29,3%. The average age of fatalities with BAT was 42,8 years and of
those without BAT 39,1 years.
Conclusion: Identification and early recognition of the risk factors
of BAT following a traffic accident is crucial for successful treatment
of patients with BAT. Front seat passengers over 50 years of age who
have been injured in a lateral collision are the most at risk of BAT.
Abstract: Cardiovascular disease mostly in the form of atherosclerosis is responsible for 30% of all world deaths amounting to 17 million people per year. Atherosclerosis is due to the formation of plaque. The fatty plaque may be at risk of rupture, leading typically to stroke and heart attack. The plaque is usually associated with a high degree of lumen reduction, called a stenosis. The initiation and progression of the disease is strongly linked to the hemodynamic environment near the vessel wall. The aim of this study is to validate the flow of blood mimic through an arterial stenosis model with computational fluid dynamics (CFD) package. In experiment, an axisymmetric model constructed consists of contraction and expansion region that follow a mathematical form of cosine function. A 30% diameter reduction was used in this study. Particle image velocimetry (PIV) was used to characterize the flow. The fluid consists of rigid spherical particles suspended in waterglycerol- NaCl mixture. The particles with 20 μm diameter were selected to follow the flow of fluid. The flow at Re=155, 270 and 390 were investigated. The experimental result is compared with FLUENT simulated flow that account for viscous laminar flow model. The results suggest that laminar flow model was sufficient to predict flow velocity at the inlet but the velocity at stenosis throat at Re =390 was overestimated. Hence, a transition to turbulent regime might have been developed at throat region as the flow rate increases.
Abstract: Three dimensional simulations in tube in tube heat
exchangers are investigated numerically in this study. In these
simulations forced convective heat transfer and laminar flow of
single-phase water are considered. In order to measure heat transfer
parameters in these heat exchangers, FLUENT CFD Solver is used in
this numerical method. For the purpose of creating geometry and
exert boundary and initial conditions in the present model, finite
volume method in Computational Fluid Dynamics is used in this
study. In the present study, at each Z-location, variation of local
temperatures, heat flux and Nusselt number at the whole tube is
investigated in detail. Thereafter, averaged computational Nusselt
number in this model is calculated. In addition, conceivable pressure
drops have been obtained at each Z-location in this model. Then,
pressure drop values in the present model are explored. Finally, all
the numerical results for this kind of heat exchanger will be discussed
precisely.
Abstract: The purpose of this study is to investigate the influence of breaststroke swimming exercise to improving the peak expiratory flow. Methode: This study used 17 students of men aged 19-21 years, APE values measured before and after the study. Style swimming workout done in accordance with a program that has been made. Result: Value of peak expiratory flow in male students obtained on average before exercise (530 ± 15 811) liters / min and after doing the exercises (540.59 ± 17 092) liters / minute. Paired ttest showed t = -6.446 and p = 0.000, which means there are differences in peak expiratory flow values before and after exercise swimming breaststroke. Conclusion: The conclusion is the breaststroke swimming exercise can be improving of peak expiratory flow.
Abstract: Wind catchers are traditional natural ventilation
systems attached to buildings in order to ventilate the indoor air. The
most common type of wind catcher is four sided one which is
capable to catch wind in all directions. CFD simulation is the perfect
way to evaluate the wind catcher performance. The accuracy of CFD
results is the issue of concern, so sensitivity analyses is crucial to
find out the effect of different settings of CFD on results. This paper
presents a series of 3D steady RANS simulations for a generic
isolated four-sided wind catcher attached to a room subjected to wind
direction ranging from 0º to 180º with an interval of 45º. The CFD
simulations are validated with detailed wind tunnel experiments. The
influence of an extensive range of computational parameters is
explored in this paper, including the resolution of the computational
grid, the size of the computational domain and the turbulence model.
This study found that CFD simulation is a reliable method for wind
catcher study, but it is less accurate in prediction of models with non
perpendicular wind directions.
Abstract: Many attempts have been made to strengthen Feistel based block ciphers. Among the successful proposals is the key- dependent S-box which was implemented in some of the high-profile ciphers. In this paper a key-dependent permutation box is proposed and implemented on DES as a case study. The new modified DES, MDES, was tested against Diehard Tests, avalanche test, and performance test. The results showed that in general MDES is more resistible to attacks than DES with negligible overhead. Therefore, it is believed that the proposed key-dependent permutation should be considered as a valuable primitive that can help strengthen the security of Substitution-Permutation Network which is a core design in many Feistel based block ciphers.
Abstract: The aim of this study was to develop a storm water quality improvement strategy plan (WQISP) which assists managers and decision makers of local city councils in enhancing their activities to improve regional water quality. City of Gosnells in Western Australia has been considered as a case study. The procedure on developing the WQISP consists of reviewing existing water quality data, identifying water quality issues in the study areas and developing a decision making tool for the officers, managers and decision makers. It was found that land use type is the main factor affecting the water quality. Therefore, activities, sources and pollutants related to different land use types including residential, industrial, agricultural and commercial are given high importance during the study. Semi-structured interviews were carried out with coordinators of different management sections of the regional councils in order to understand the associated management framework and issues. The issues identified from these interviews were used in preparing the decision making tool. Variables associated with the defined “value versus threat" decision making tool are obtained from the intensive literature review. The main recommendations provided for improvement of water quality in local city councils, include non-structural, structural and management controls and potential impacts of climate change.
Abstract: The development of the power electronics has allowed
increasing the precision and reliability of the electrical devices, thanks
to the adjustable inverters, as the Pulse Wide Modulation (PWM)
applied to the three level inverters, which is the object of this study.
The authors treat the relation between the law order adopted for a
given system and the oscillations of the electrical and mechanical
parameters of which the tolerance depends on the process with which
they are integrated (paper factory, lifting of the heavy loads,
etc.).Thus, the best choice of the regulation indexes allows us to
achieve stability and safety training without investment (management
of existing equipment). The optimal behavior of any electric device
can be achieved by the minimization of the stored electrical and
mechanical energy.
Abstract: The class of geometric deformable models, so-called
level sets, has brought tremendous impact to medical imagery. In
this paper we present yet another application of level sets to medical
imaging. The method we give here will in a way modify the speed
term in the standard level sets equation of motion. To do so we
build a potential based on the distance and the gradient of the
image we study. In turn the potential gives rise to the force field:
F~F(x, y) = P
∀(p,q)∈I
((x, y) - (p, q)) |ÔêçI(p,q)|
|(x,y)-(p,q)|
2 . The direction
and intensity of the force field at each point will determine the
direction of the contour-s evolution. The images we used to test
our method were produced by the Univesit'e de Sherbrooke-s PET
scanners.
Abstract: Well-being has been given special emphasis in quality
of life. It involves living a meaningful, life satisfaction, stability and
happiness in life. Well-being also concerns the satisfaction of
physical, psychological, social needs and demands of an individual.
The purpose of this study was to validate three-factor measurement
model of well-being using structural equation modeling (SEM). The
conceptions of well-being measured such dimensions as physical,
psychological and social well-being. This study was done based on a
total sample of 650 adolescents from east-coast of peninsular
Malaysia. The Well-Being Scales which was adapted from [1] was
used in this study. The items were hypothesized a priori to have nonzero
loadings on all dimensions in the model. The findings of the
SEM demonstrated that it is a good fitting model which the proposed
model fits the driving theory; (x2df = 1.268; GFI = .994; CFI = .998;
TLI= .996; p = .255; RMSEA = .021). Composite reliability (CR)
was .93 and average variance extracted (AVE) was 58%. The model
in this study fits with the sample of data and well-being is important
to bring sustainable development to the mainstream.
Abstract: The aim of this qualitative case study is to examine how school principals perform their new roles and responsibilities defined in accordance with the new curriculum. Of ten primary schools that the new curriculum was piloted in Istanbul in school year of 2004-2005, one school was randomly selected as the sample of the study. The participants of the study were comprised of randomly-selected 26 teachers working in the case school. To collect data, an interview schedule was developed based on the new role definitions for school principals by the National Ministry of Education. Participants were interviewed on one-to-one basis in February and March 2007. Overall results showed that the school principal was perceived to be successful in terms of the application of the new curriculum in school. According to the majority of teachers, the principal has done his best to establish the infrastructure that is necessary for successful application of the new program. In addition to these, the principal was reported to adopt a collegial and participatory leadership style by creating a positive school atmosphere that enables the school community (teachers, parents and students) to involve school more than before. Keywordscase study, curriculum implementation, school principals and curriculum
Abstract: Quality costs are the costs associated with preventing,
finding, and correcting defective work. Since the main language of
corporate management is money, quality-related costs act as means of
communication between the staff of quality engineering departments
and the company managers. The objective of quality engineering is to
minimize the total quality cost across the life of product. Quality
costs provide a benchmark against which improvement can be
measured over time. It provides a rupee-based report on quality
improvement efforts. It is an effective tool to identify, prioritize and
select quality improvement projects. After reviewing through the
literature it was noticed that a simplified methodology for data
collection of quality cost in a manufacturing industry was required.
The quantified standard methodology is proposed for collecting data
of various elements of quality cost categories for manufacturing
industry. Also in the light of research carried out so far, it is felt
necessary to standardise cost elements in each of the prevention,
appraisal, internal failure and external failure costs. . Here an attempt
is made to standardise the various cost elements applicable to
manufacturing industry and data is collected by using the proposed
quantified methodology. This paper discusses the case study carried
in luggage manufacturing industry.