Abstract: A novel method to produce a fast high voltage solid
states switch using Insulated Gate Bipolar Transistors (IGBTs) is
presented for discharge-pumped gas lasers. The IGBTs are connected
in series to achieve a high voltage rating. An avalanche transistor is
used as the gate driver. The fast pulse generated by the avalanche
transistor quickly charges the large input capacitance of the IGBT,
resulting in a switch out of a fast high-voltage pulse. The switching
characteristic of fast-high voltage solid state switch has been estimated
in the multi-stage series-connected IGBT with the applied voltage of
several tens of kV. Electrical circuit diagram and the mythology of
fast-high voltage solid state switch as well as experimental results
obtained are presented.
Abstract: The postharvest quality management of tomatoes is
important to limit the amount of losses that occur due to deterioration
between harvest and consumption. This study was undertaken to
investigate the effects of pre- and postharvest integrated agrotechnologies,
involving greenhouse microclimate and postharvest
storage conditions, on the postharvest quality attributes of four
tomato cultivars. Tomato fruit firmness, colour (hue angle (h°) and
L* value), pH and total soluble solids for the cultivars Bona,
Star 9037, Star 9009 and Zeal, grown in a fan-pad evaporativelycooled
and an open-ended naturally-ventilated tunnel, were harvested
at the mature-green stage. The tomatoes were stored for 28 days
under cold storage conditions, with a temperature of 13°C and RH of
85%, and under ambient air conditions, with a temperature of 23±
2°C and RH of 52± 4%. This study has provided information on the
effect of integrated pre-harvest and postharvest agro-technologies,
involving greenhouse microclimate and postharvest storage
environment on the postharvest quality attributes of four of the
tomato cultivars in South Africa. NVT-grown tomatoes retained
better textural qualities, but ripened faster by changing from green to
red faster, although these were reduced under cold storage conditions.
FPVT-grown tomatoes had lower firmness, but ripened slowly with
higher colour attributes. With cold storage conditions, the firmness of
FPVT-grown tomatoes was maintained. Cultivar Bona firmness and
colour qualities depreciated the fastest, but it had higher TSS content
and lower pH values. Star 9009 and Star 9037 presented better
quality, by retaining higher firmness and ripening slowly, but they
had the lowest TSS contents and high pH values, especially
Star 9037. Cold storage improved the firmness of tomato cultivars
with poor textural quality and faster colour changes.
Abstract: This paper is drawn from a wider study of the
management of gender, age and disability diversity in the banking
sector in the Kingdom of Saudi Arabia (KSA), which aims to develop
a framework for diversity management (DM) in this sector. The
paper focuses on the management of disability diversity. The purpose
of the paper is to assist in understanding disability DM in the banking
sector in KSA and to make suggestions for its enhancement. Hence, it
contributes to filling a research gap, as there is a dearth of literature
on disability DM, in KSA in general, and in the banking sector
specifically.
Discrimination against people with disabilities is a social issue that
has not been entirely overcome in any society. However, in KSA,
Islam informs almost every aspect of daily life including work, and
Islam is against discrimination. Hence, in KSA, there are regulations
to accommodate people with disabilities; however, employers are still
free not to hire job applicants with disabilities specifically because of
their condition. Indeed, disabled people are almost entirely absent
from the labour market.
There are 12 Saudi-owned or part-Saudi-owned banks in KSA and
two managers from each of these were interviewed, making a total of
24. The interviews aimed to investigate empirically the understanding
of managers in the banking sector in KSA of diversity management,
including disability DM, in the banking sector. The interview data
were analysed using thematic analysis. Two interviewees stated that
banks used the employment of people with disabilities to enhance
their corporate image, while five expressed the opinion that disabled
employees could contribute to the bank provided they did not have to
deal with customers face-to-face. Nine of the interviewees perceived
that disabled employees could be of value to the bank for their own
sake, not only in ‘behind the scenes’ roles. Another two interviewees
mentioned that employing disabled people could be part of the bank’s
community service programme and one thought it would be part of
the bank’s Saudisation efforts. The remaining five interviewees did
not know how disabled people could contribute to the bank.
The findings show that disability DM in the banking sector in
KSA is a relatively new concept, and is not yet well understood. In
the light of the findings, in order to achieve the purpose of the paper,
the following suggestions were made for the enhancement of
disability DM in the banking sector in KSA. A change in attitudes
towards disabled people is necessary. Such a change in the workplace
can only be achieved if a top-down approach is taken to the
integration of disabled people. Hence, it is suggested that
management and employees follow a course in disability awareness.
Further, a diversity officer in the HR department could enhance the
integration of disabled people into the banking workforce. It is also
suggested that greater government support is required through closely
monitored and enforced anti-discrimination legislation. Moreover,
flexible working arrangements such as part-time work would
facilitate the employment of disabled people and benefit other groups
of employees.
Abstract: GRF, Growth regulating factor, genes encode a novel
class of plant-specific transcription factors. The GRF proteins play a
role in the regulation of cell numbers in young and growing tissues
and may act as transcription activations in growth and development
of plants. Identification of GRF genes and their expression are
important in plants to performance of the growth and development of
various organs. In this study, to better understanding the structural
and functional differences of GRFs family, 45 GRF proteins
sequences in A. thaliana, Z. mays, O. sativa, B. napus, B. rapa, H.
vulgare and S. bicolor, have been collected and analyzed through
bioinformatics data mining. As a result, in secondary structure of
GRFs, the number of alpha helices was more than beta sheets and in
all of them QLQ domains were completely in the biggest alpha helix.
In all GRFs, QLQ and WRC domains were completely protected
except in AtGRF9. These proteins have no trans-membrane domain
and due to have nuclear localization signals act in nuclear and they
are component of unstable proteins in the test tube.
Abstract: The substantial similarity of fatigue mechanism in a
new test rig for rolling contact fatigue (RCF) has been investigated. A
new reduced-scale test rig is designed to perform controlled RCF
tests in wheel-rail materials. The fatigue mechanism of the rig is
evaluated in this study using a combined finite element-fatigue
prediction approach. The influences of loading conditions on fatigue
crack initiation have been studied. Furthermore, the effects of some
artificial defects (squat-shape) on fatigue lives are examined. To
simulate the vehicle-track interaction by means of the test rig, a threedimensional
finite element (FE) model is built up. The nonlinear
material behaviour of the rail steel is modelled in the contact
interface. The results of FE simulations are combined with the critical
plane concept to determine the material points with the greatest
possibility of fatigue failure. Based on the stress-strain responses, by
employing of previously postulated criteria for fatigue crack initiation
(plastic shakedown and ratchetting), fatigue life analysis is carried
out. The results are reported for various loading conditions and
different defect sizes. Afterward, the cyclic mechanism of the test rig
is evaluated from the operational viewpoint. The results of fatigue
life predictions are compared with the expected number of cycles of
the test rig by its cyclic nature. Finally, the estimative duration of the
experiments until fatigue crack initiation is roughly determined.
Abstract: One of the most important tasks in the risk
management is the correct determination of probability of default
(PD) of particular financial subjects. In this paper a possibility of
determination of financial institution’s PD according to the creditscoring
models is discussed. The paper is divided into the two parts.
The first part is devoted to the estimation of the three different
models (based on the linear discriminant analysis, logit regression
and probit regression) from the sample of almost three hundred US
commercial banks. Afterwards these models are compared and
verified on the control sample with the view to choose the best one.
The second part of the paper is aimed at the application of the chosen
model on the portfolio of three key Czech banks to estimate their
present financial stability. However, it is not less important to be able
to estimate the evolution of PD in the future. For this reason, the
second task in this paper is to estimate the probability distribution of
the future PD for the Czech banks. So, there are sampled randomly
the values of particular indicators and estimated the PDs’ distribution,
while it’s assumed that the indicators are distributed according to the
multidimensional subordinated Lévy model (Variance Gamma model
and Normal Inverse Gaussian model, particularly). Although the
obtained results show that all banks are relatively healthy, there is
still high chance that “a financial crisis” will occur, at least in terms
of probability. This is indicated by estimation of the various quantiles
in the estimated distributions. Finally, it should be noted that the
applicability of the estimated model (with respect to the used data) is
limited to the recessionary phase of the financial market.
Abstract: A single-phase closed thermosyphon has been
fabricated and experimented to utilize solar energy for water heating.
The working fluid of the closed thermosyphon is heated at the flatplate
collector and the hot water goes to the water tank due to density
gradient caused by temperature differences. This experimental work
was done using insulated water tank and insulated connecting pipe
between the tank and the flat-plate collector. From the collected data,
performance parameters such as instantaneous collector efficiency
and heat removal factor are calculated. In this study, the effects of
glazing were also observed. The water temperature rise and the
maximum instantaneous efficiency obtained from this experiment
with glazing using insulated water tank and insulated connecting pipe
are 17°C in a period of 5 hours and 60% respectively. Whereas the
water temperature rise and the maximum instantaneous efficiency
obtained from this experiment with glazing using non-insulated water
tank and non-insulated connecting pipe are 14°C in a period of 5
hours and 39% respectively.
Abstract: In structures, stress concentration is a factor of fatigue
fracture. Basically, the stress concentration is a phenomenon that
should be avoided. However, it is difficult to avoid the stress
concentration. Therefore, relaxation of the stress concentration is
important. The stress concentration arises from notches and circular
holes. There is a relaxation method that a composite patch covers a
notch and a circular hole. This relaxation method is used to repair
aerial wings, but it is not systematized. Composites are more
expensive than single materials. Accordingly, we propose the
relaxation method that a single material patch covers a notch and a
circular hole, and aim to systematize this relaxation method.
We performed FEA (Finite Element Analysis) about an object by
using a three-dimensional FEA model. The object was that a patch
adheres to a plate with a circular hole. And, a uniaxial tensile load acts
on the patched plate with a circular hole. In the three-dimensional FEA
model, it is not easy to model the adhesion layer. Basically, the yield
stress of the adhesive is smaller than that of adherents. Accordingly,
the adhesion layer gets to plastic deformation earlier than the adherents
under the yield load of adherents. Therefore, we propose the
three-dimensional FEA model which is applied a nonlinear elastic
region to the adhesion layer. The nonlinear elastic region was
calculated by a bilinear approximation. We compared the analysis
results with the tensile test results to confirm whether the analysis
model has usefulness. As a result, the analysis results agreed with the
tensile test results. And, we confirmed that the analysis model has
usefulness.
As a result that the three-dimensional FEA model was used to the
analysis, it was confirmed that an out-of-plane deformation occurred
to the patched plate with a circular hole. The out-of-plane deformation
causes stress increase of the patched plate with a circular hole.
Therefore, we investigated that the out-of-plane deformation affects
relaxation of the stress concentration in the plate with a circular hole
on this relaxation method. As a result, it was confirmed that the
out-of-plane deformation inhibits relaxation of the stress concentration
on the plate with a circular hole.
Abstract: Supermarkets are the most electricity-intensive type of
commercial buildings. The unsuitable indoor environment of a
supermarket provided by abnormal HVAC operations incurs waste
energy consumption in refrigeration systems. This current study
briefly describes significantly solid backgrounds and proposes easyto-
use analysis terminology for investigating the impact of HVAC
operations on refrigeration power consumption using the field-test
data obtained from building automation system (BAS). With solid
backgrounds and prior knowledge, expected energy interactions
between HVAC and refrigeration systems are proposed through
Pearson’s correlation analysis (R value) by considering correlations
between equipment power consumption and dominantly independent
variables (driving force conditions).The R value can be conveniently
utilized to evaluate how strong relations between equipment
operations and driving force parameters are. The calculated R values
obtained from field data are compared to expected ranges of R values
computed by energy interaction methodology. The comparisons can
separate the operational conditions of equipment into faulty and
normal conditions. This analysis can simply investigate the condition
of equipment operations or building sensors because equipment could
be abnormal conditions due to routine operations or faulty
commissioning processes in field tests. With systematically solid and
easy-to-use backgrounds of interactions provided in the present
article, the procedures can be utilized as a tool to evaluate the proper
commissioning and routine operations of HVAC and refrigeration
systems to detect simple faults (e.g. sensors and driving force
environment of refrigeration systems and equipment set-point) and
optimize power consumption in supermarket buildings. Moreover,
the analysis will be used to further study the FDD research for
supermarkets in future.
Abstract: Apps are today the most important possibility to adapt
mobile phones and computers to fulfill the special needs of their
users. Location- and context-sensitive programs are hereby the key to
support the interaction of the user with his/her environment and also
to avoid an overload with a plenty of dispensable information. The
contribution shows, how a trusted, secure and really bi-directional
communication and interaction among users and their environment
can be established and used, e.g. in the field of home automation.
Abstract: The psychological impact of peer influence on its
individual group members, can make them resist HIV/AIDS
counselling and testing. This study investigated the correlate of peer
influence and resistance to HIV/AIDS counselling and testing among
students in tertiary institutions in Kano state, Nigeria. To achieve
this, three null hypotheses were postulated and tested. Cross-
Sectional Survey Design was employed in which 1512 sample was
selected from a student population of 104,841.Simple Random
Sampling was used in the selection. A self-developed 20-item scale
called Peer Influence and Psychological Resistance Inventory
(PIPRI) was used for data collection. Pearson Product Moment
Correlation (PPMCC) via test-retest method was applied to estimate a
reliability coefficient of 0.86 for the scale. Data obtained was
analyzed using t-test and PPMCC at 0.05 level of confidence. Results
reveal 26.3% (397) of the respondents being influenced by their peer
group, while 39.8% showed resistance. Also, the t-tests and PPMCC
statistics were greater than their respective critical values. This shows
that there was a significant gender difference in peer influence and a
difference between peer influence and resistance to HIV/AIDS
counselling and testing. However, a positive relationship between
peer influence and resistance to HIV/AIDS counselling and testing
was shown. A major recommendation offered suggests the use of
reinforcement and social support for positive attitudes and
maintenance of safe behaviour among students who patronize
HIV/AIDS counselling.
Abstract: Cement-based grouts has been used successfully to
repair cracks in many concrete structures such as bridges, tunnels,
buildings and to consolidate soils or rock foundations. In the present
study the rheological characterization of cement grout with
water/binder ratio (W/B) is fixed at 0.5. The effect of the replacement
of cement by bentonite (2 to 10% wt) in presence of superplasticizer
(0.5% wt) was investigated. Several rheological tests were carried out
by using controlled-stress rheometer equipped with vane geometry in
temperature of 20°C. To highlight the influence of bentonite and
superplasticizer on the rheological behavior of grout cement, various
flow tests in a range of shear rate from 0 to 200 s-1 were observed.
Cement grout showed a non-Newtonian viscosity behavior at all
concentrations of bentonite. Three parameter model Herschel-
Bulkley was chosen for fitting of experimental data. Based on the
values of correlation coefficients of the estimated parameters, The
Herschel-Bulkley law model well described the rheological behavior
of the grouts. Test results showed that the dosage of bentonite
increases the viscosity and yield stress of the system and introduces
more thixotropy. While the addition of both bentonite and
superplasticizer with cement grout improve significantly the fluidity
and reduced the yield stress due to the action of dispersion of SP.
Abstract: The development of the agricultural sector in Ghana
has been reliant on the use of irrigation systems to ensure food
security. However, the manual operation of these systems has not
facilitated their maximum efficiency due to human limitations.
This paper seeks to address this problem by designing and
implementing an efficient, cost effective automated system which
monitors and controls the water flow of irrigation through
communication with an authorized operator via text messages. The
automatic control component of the system is timer based with an
Atmega32 microcontroller and a real time clock from the SM5100B
cellular module. For monitoring purposes, the system sends periodic
notification of the system on the performance of duty via SMS to the
authorized person(s). Moreover, the GSM based Irrigation
Monitoring and Control System saves time and labour and reduces
cost of operating irrigation systems by saving electricity usage and
conserving water.
Field tests conducted have proven its operational efficiency and
ease of assessment of farm irrigation equipment due to its costeffectiveness
and data logging capabilities.
Abstract: Microarray technology is universally used in the study
of disease diagnosis using gene expression levels. The main
shortcoming of gene expression data is that it includes thousands of
genes and a small number of samples. Abundant methods and
techniques have been proposed for tumor classification using
microarray gene expression data. Feature or gene selection methods
can be used to mine the genes that directly involve in the
classification and to eliminate irrelevant genes. In this paper
statistical measures like T-Statistics, Signal-to-Noise Ratio (SNR)
and F-Statistics are used to rank the genes. The ranked genes are used
for further classification. Particle Swarm Optimization (PSO)
algorithm and Shuffled Frog Leaping (SFL) algorithm are used to
find the significant genes from the top-m ranked genes. The Naïve
Bayes Classifier (NBC) is used to classify the samples based on the
significant genes. The proposed work is applied on Lung and Ovarian
datasets. The experimental results show that the proposed method
achieves 100% accuracy in all the three datasets and the results are
compared with previous works.
Abstract: Students’ achievement and motivation in learning
English in Malaysia is a worrying trend as it is lagging behind several
other countries in Asia. Thus, necessary actions have to be taken by
the parties concerned to overcome this problem. The purpose of this
research was to study the effects of drill and practice courseware on
students’ achievement and motivation in learning English language.
A multimedia courseware was developed for this purpose. The
independent variable was the drill and practice courseware while the
dependent variables were the students’ achievement and motivation.
Their achievement was measured using pre-test and post-test scores,
while motivation was measured using a questionnaire. A total of 60
students from three vernacular primary schools in a northern state in
Malaysia were randomly selected in this study. The findings indicate:
(1) a significant difference between the students’ pre-test and posttest
scores after using the courseware, (2) no significant difference in
the achievement score between male and female students after using
the courseware, (3) a significant difference in motivation score
between the female and the male students, and (4) while the female
students scored significantly higher than the male students in the
aspects of relevance, confidence and satisfaction, no significant
difference in terms of attention was observed between them. Overall,
the findings clearly indicate that although the female students are
significantly more motivated than their male students, they are
equally good in terms of achievement after learning from the
courseware. Through this study, the drill and practice courseware is
proven to influence the students’ learning and motivation.
Abstract: The asynchronous discussion forum is one of the most
widely used activities in learning management system environment.
Online forum allows participants to interact, construct knowledge,
and can be used to complement face to face sessions in blended
learning courses. However, to what extent do the students perceive
the benefits or advantages of forum remain to be seen. Through
content and social network analyses, instructors will be able to gauge
the students’ engagement and knowledge construction level. Thus,
this study aims to analyze the students’ level of knowledge
construction and their participation level that occur through online
discussion. It also attempts to investigate the relationship between the
level of knowledge construction and their social interaction patterns.
The sample involves 23 students undertaking a master course in one
public university in Malaysia. The asynchronous discussion forum
was conducted for three weeks as part of the course requirement. The
finding indicates that the level of knowledge construction is quite
low. Also, the density value of 0.11 indicating the overall
communication among the participants in the forum is low. This
study reveals that strong and significant correlations between SNA
measures (in-degree centrality, out-degree centrality) and level of
knowledge construction. Thus, allocating these active students in
different group aids the interactive discussion takes place. Finally,
based upon the findings, some recommendations to increase students’
level of knowledge construction and also for further research are
proposed.
Abstract: Stochastic User Equilibrium (SUE) model is a widely
used traffic assignment model in transportation planning, which is
regarded more advanced than Deterministic User Equilibrium (DUE)
model. However, a problem exists that the performance of the SUE
model depends on its error term parameter. The objective of this
paper is to propose a systematic method of determining the
appropriate error term parameter value for the SUE model. First, the
significance of the parameter is explored through a numerical
example. Second, the parameter calibration method is developed
based on the Logit-based route choice model. The calibration process
is realized through multiple nonlinear regression, using sequential
quadratic programming combined with least square method. Finally,
case analysis is conducted to demonstrate the application of the
calibration process and validate the better performance of the SUE
model calibrated by the proposed method compared to the SUE
models under other parameter values and the DUE model.
Abstract: The 1/f noise investigation in nanoscale light-emitting
diodes and lasers, based on GaAs and alloys, is presented here.
Leakage and additional (to recombination through quantum wells
and/or dots) nonlinear currents were detected and it was shown that
these currents are the main source of the 1/f noise in devices studied.
Abstract: Human movement in the real world provides
important information for developing human behaviour models and
simulations. However, it is difficult to assess ‘real’ human behaviour
since there is no established method available. As part of the AUNTSUE
(Accessibility and User Needs in Transport – Sustainable Urban
Environments) project, this research aimed to propose a method to
assess human movement and behaviour in crowded areas. The
method is based on the three major steps of video recording,
conceptual behavior modelling and video analysis. The focus is on
individual human movement and behaviour in normal situations
(panic situations are not considered) and the interactions between
individuals in localized areas. Emphasis is placed on gaining
knowledge of characteristics of human movement and behaviour in
the real world that can be modelled in the virtual environment.
Abstract: This paper explores the effects of gamification on
lower secondary school students’ motivation and engagement in the
classroom. Two-group posttest-only experimental design were
employed to study the influence of gamification teaching method
(GTM) when compared with conventional teaching method (CTM)
on 60 lower secondary school students. The Student Engagement
Instrument (SEI) and Intrinsic Motivation Inventory (IMI) were used
to assess students’ intrinsic motivation and engagement level towards
the respective teaching method. Finding indicates that students who
completed the GTM lesson were significantly higher in intrinsic
motivation to learn than those from the CTM. Although the result
were insignificant and only marginal difference in the engagement
mean, GTM still show better potential in raising student’s
engagement in class when compared with CTM. This finding proves
that the GTM is likely to solve the current issue of low motivation to
learn and low engagement in class among lower secondary school
students in Malaysia. On the other hand, despite being not significant,
higher mean indicates that CTM positively contribute to higher peer
support for learning and better teacher and student relationship when
compared with GTM. As a conclusion, gamification approach is
flexible and can be adapted into many learning content to enhance the
intrinsic motivation to learn and to some extent, encourage better
student engagement in class.