Abstract: In this paper two approaches to joint signal detection,
time of arrival (ToA) and angle of arrival (AoA) estimation in
multi-element antenna array are investigated. Two scenarios were
considered: first one, when the waveform of the useful signal
is known a priori and, second one, when the waveform of the
desired signal is unknown. For first scenario, the antenna array
signal processing based on multi-element matched filtering (MF)
with the following non-coherent detection scheme and maximum
likelihood (ML) parameter estimation blocks is exploited. For second
scenario, the signal processing based on the antenna array elements
covariance matrix estimation with the following eigenvector analysis
and ML parameter estimation blocks is applied. The performance
characteristics of both signal processing schemes are thoroughly
investigated and compared for different useful signals and noise
parameters.
Abstract: The Port of Townsville conducts regular annual
maintenance dredging to maintain depths of its harbor basin and
approach channels for the navigational safety of the vessels against
the natural accumulation of marine sediments. In addition to the
regular maintenance dredging, the port undertakes emergency
dredging in cases where large quantities of sediments are mobilized
and deposited in port waters by cyclone or major flood events. The
maintenance dredging material derived from the port may be
disposed at sea or on land in accordance with relevant state and
commonwealth regulations. For the land disposal, the dredged mud
slurry is hydraulically placed into containment ponds and left to
undergo sedimentation and self-weight consolidation to form fill
material for land reclamation. This paper provides an overview of the
maintenance dredging at the Port of Townsville and emphasis on
maintenance dredging requirements, sediment quality, bathymetry,
dredging methods used, and dredged material disposal options.
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: The parameters of a two-layer soil can be determined by
processing resistivity data obtained from resistivity measurements
carried out on the soil of interest. The processing usually entails
applying the resistivity data as inputs to an optimisation function.
This paper proposes an algorithm which utilises the square error as an
optimisation function. Resistivity data from previous works were
applied to test the accuracy of the new algorithm developed and the
result obtained conforms significantly to results from previous works.
Abstract: The purpose of the present work is to review some
data for the management challenges that the aquaculture industry in
Greece is currently facing. The results indicate that Greek
aquaculture fish farms apply Human Resources Management (HRM)
practices which can increase motivation, commitment and job
satisfaction of their personnel. In turn, these practices can increase
the productivity of the business. The Greek fish farms appear to
invest in research and technological innovation with a good record in
research activities and the generation of patents. Interestingly, the
results of the present work were carried out during the period of the
recent economic crisis in Greece. Several sectors of the Greek
economy were severely affected by the financial problems of the
Greek government and the Greek banks. Under the adverse
economical conditions created by the Greek economic crisis, even the
Greek aquaculture industry, which historically is considered as a
thriving national exporting business sector, experienced harsh
economic and market conditions. As a result of the global, European
and national economic crisis, consumption of fish dropped while
companies had to hold most of their stocked fish in order to regulated
the flow to the market and the price. This occurred at a time where
Banks in Greece had their own financial crisis – banking crisis -
which resulted in limited access to lending for the all business sectors
of the national economy including the Greek aquaculture industry. In
spite of these economic conditions, the Greek aquaculture industry,
after a series of mergers and acquisitions, has now stabilized
production and exhibits very good prospects for future growth.
Evidently, the firms had to cut salaries and on some occasions even
pay their staff in arrears. Nevertheless, the results presented in this
paper indicate that during the economic crisis, the surveyed fish
farms maintained their HRM practices, investing in their human
capital and technological input. In fact, human capital and
technological input are the ticket for future success of companies in
any business sector.
Abstract: Mech-Degla, Degla-Beida and Frezza are the date
(Phoenix dactylifera L.) common varieties with a more or less good
availability and feeble trade value. Some morphologic and
physicochemical factors were determined. Results show that the
whole date weight is significantly different (P= 95%) concerning
Mech-Degla and Degla-Beida which are more commercialized than
Frezza whereas the pulp mass proportion in relation to whole fruits is
highest for Frezza (88.28%). Moreover, there is a large variability
concerning the weights and densities of constitutive tissues in each
variety. The white tissue is dominant in Mech-Degla in opposite to
the two other varieties. The variance analyze showed that the
difference in weights between brown and white tissues is significant
(P = 95%) for all studied varieties. Some other morphologic and
chemical proprieties of the whole pulps and their two constitutive
parts (brown or pigmented and white) are also investigated. The
predominance of phenolics in Mech-Degla (4.01g/100g, w.b) and
Frezza (4.96 g/100g, w.b) pulps brown part is the main result
revealed in this study.
Abstract: Identification and selection of appropriate product and
manufacturing technologies are key factors for competitiveness and
market success of technology-based companies. Therefore, many
companies perform technology intelligence (TI) activities to ensure
the identification of evolving technologies at the right time.
Technology monitoring is one of the three base activities of TI,
besides scanning and scouting.
As the technological progress is accelerating, more and more
technologies are being developed. Against the background of limited
resources it is therefore necessary to focus TI activities. In this paper
we propose a concept for defining appropriate search fields for
technology monitoring. This limitation of search space leads to more
concentrated monitoring activities. The concept will be introduced
and demonstrated through an anonymized case study conducted
within an industry project at the Fraunhofer Institute for Production
Technology IPT.
The described concept provides a customized monitoring
approach, which is suitable for use in technology-oriented companies.
It is shown in this paper that the definition of search fields and search
tasks are suitable methods to define topics of interest and thus to
align monitoring activities. Current as well as planned product,
production and material technologies and existing skills, capabilities
and resources form the basis for derivation of relevant search areas.
To further improve the concept of technology monitoring the
proposed concept should be extended during future research e.g. by
the definition of relevant monitoring parameters.
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.
Abstract: Online forum is part of a Learning Management
System (LMS) environment in which students share their opinions.
This study attempts to investigate the perceptions of students towards
online forum and their patterns of listening behavior during the forum
interaction. The students’ perceptions were measured using a
questionnaire, in which seven dimensions were used involving online
experience, benefits of forum participation, cost of participation,
perceived ease of use, usefulness, attitude, and intention. Meanwhile,
their patterns of listening behaviors were obtained using the log file
extracted from the LMS. A total of 25 postgraduate students
undertaking a course were involved in this study, and their activities
in the forum session were recorded by the LMS and used as a log file.
The results from the questionnaire analysis indicated that the students
perceived that the forum is easy to use, useful, and bring benefits to
them. Also, they showed positive attitude towards online forum, and
they have the intention to use it in future. Based on the log data, the
participants were also divided into six clusters of listening behavior,
in which they are different in terms of temporality, breadth, depth and
speaking level. The findings were compared to previous clusters
grouping and future recommendations are also discussed.
Abstract: A study was conducted to determine the diversity and
abundance of shorebird species habituating the mudflat area of Jeram
Beach and Remis Beach, Selangor, Peninsular Malaysia. Direct
observation technique (using binoculars and video camera) was
applied to record the presence of bird species in the sampling sites
from August 2013 until July 2014. A total of 32 species of shorebird
were recorded during both migratory and non-migratory seasons. Of
these, eleven species (48%) are migrants, six species (26%) have both
migrant and resident populations, four species (17%) are vagrants and
two species (9%) are residents. The compositions of the birds
differed significantly in all months (χ2 = 84.35, p < 0.001). There is a
significant difference in avian abundance between migratory and
non-migratory seasons (Mann-Whitney, t = 2.39, p = 0.036). The
avian abundance were differed significantly in Jeram and Remis
Beaches during migratory periods (t = 4.39, p = 0.001) but not during
non-migratory periods (t = 0.78, p = 0.456). Shorebird diversity was
also affected by tidal cycle. There is a significance difference
between high tide and low tide (Mann-Whitney, t = 78.0, p < 0.005).
Frequency of disturbance also affected the shorebird distribution
(Mann-Whitney, t = 57.0, p = 0.0134). Therefore, this study
concluded that tides and disturbances are two factors that affecting
temporal distribution of shorebird in mudflats area.
Abstract: This research aims to investigate callus induction,
somatic embryogenesis and indirect plant regeneration of Crassula
ovata (Mill.) Druce – the famous ornamental plant. Experiment no.1:
Callus induction was obtained from leaf and stem explants on
Murashige and Skoog (MS) medium supplemented with various plant
growth regulators (PGRs). Effects of different PGRs, plant
regeneration and subsequent plantlet conversion were also assessed.
Indirect plant regeneration was achieved from the callus of stem
explants by the addition of 1.5 mg/L Kinetin (KN) alone. Best shoot
induction was achieved (6.5 shoots/per explant) after 60 days. For
successful rooting, regenerated plantlets were sub-cultured on the
same MS media supplemented with 1.5 mg/L KN alone. The rooted
plantlets were acclimatized and the survival rate was 90%.
Experiment no.2: Results revealed that 0.5 mg/L 2,4-D alone and in
combination with 1.0 mg/L 6-Benzyladenine (BA) gave 89.8% callus
from the stem explants as compared to leaf explants. Callus
proliferation and somatic embryo formation were also evaluated by
‘Double Staining Method’ and different stages of somatic
embryogenesis were revealed by scanning electron microscope. Full
Strength MS medium produced the highest number (49.6%) of
cotyledonary stage somatic embryos (SEs). Mature cotyledonary
stage SEs developed into plantlets after 12 weeks of culture. Wellrooted
plantlets were successfully acclimatized at the survival rate of
85%. Indirectly regenerated plants did not show any detectable
variation in morphological and growth characteristics when
compared with the donor plant.
Abstract: This paper presents a method for the efficient
implementation of a unidirectional or bidirectional DC/DC converter.
The DC/DC converter is used essentially for energy exchange
between the low voltage service battery and a high voltage battery
commonly found in Electric Vehicle applications. In these
applications, apart from cost, efficiency of design is an important
characteristic. A useful way to reduce the size of electronic
equipment in the electric vehicles is proposed in this paper. The
technique simplifies the mechanical complexity and maximizes the
energy usage using the latest converter control techniques. Moreover
a bidirectional battery charger for hybrid electric vehicles is also
implemented in this paper. Several simulations on the test system
have been carried out in Matlab/Simulink environment. The results
exemplify the robustness of the proposed design methodology in case
of a 1.5 KW DC-DC converter.
Abstract: This paper presents a comparison between using a
desktop web application and a mobile application for students
enrolling in courses at Rangsit University, Thailand. In addition,
Rangsit University has enhanced the enrollment process by
leveraging its information systems, which allows students to choose
to enroll in courses online. In order to use the system, students must
provide their identification and personal documents for registration.
The reason to have a mobile application is to support students’ ability
to access the system at anytime, anywhere and anyplace. The
objective of this paper was to: 1. Evaluate the success of developing a
user friendly mobile device system and 2. Measure user interest in
future mobile development.
Abstract: This study proposes the transformation of nonlinear
Magnetic Levitation System into linear one, via state and feedback
transformations using explicit algorithm. This algorithm allows
computing explicitly the linearizing state coordinates and feedback
for any nonlinear control system, which is feedback linearizable,
without solving the Partial Differential Equations. The algorithm is
performed using a maximum of N-1 steps where N being the
dimension of the system.
Abstract: The study was conducted to evaluate the efficiency of
Garlic and Chili combination solution on control of insect pests in
cabbage crop. The solution was sprayed at different intervals after
transplanting. The efficiency of Garlic and chili combination solution
on cabbage insect pests was measured. Results revealed that Garlic
and chili combination solution was the effectively reduced cabbage
insect pests. On other hand, the spray solution not only reduced the
number of days required for the cabbage growth but also greatly
enhanced the leaf number, head diameter, head weight, and quality of
cabbage. Garlic and chili combination solution have positive effects
on pests reduction and improve growth, yield and quality of cabbage
vegetable.
Abstract: In MANET, mobile nodes communicate with each
other using the wireless channel where transmission takes place with
significant interference. The wireless medium used in MANET is a
shared resource used by all the nodes available in MANET. Packet
reserving is one important resource management scheme which
controls the allocation of bandwidth among multiple flows through
node cooperation in MANET. This paper proposes packet reserving
and clogging control via Routing Aware Packet Reserving (RAPR)
framework in MANET. It mainly focuses the end-to-end routing
condition with maximal throughput. RAPR is complimentary system
where the packet reserving utilizes local routing information
available in each node. Path setup in RAPR estimates the security
level of the system, and symbolizes the end-to-end routing by
controlling the clogging. RAPR reaches the packet to the destination
with high probability ratio and minimal delay count. The standard
performance measures such as network security level,
communication overhead, end-to-end throughput, resource utilization
efficiency and delay measure are considered in this work. The results
reveals that the proposed packet reservation and clogging control via
Routing Aware Packet Reserving (RAPR) framework performs well
for the above said performance measures compare to the existing
methods.
Abstract: Nonstandard tests are necessary for analyses and
verification of new developed structural and technological solutions
with application of composite materials. One of the most critical
primary structural parts of a typical aerospace structure is T-joint.
This structural element is loaded mainly in shear, bending, peel and
tension. The paper is focused on the shear loading simulations. The
aim of the work is to obtain a representative uniform distribution of
shear loads along T-joint during the mechanical testing. A new
design of T-joint test procedure, numerical simulation and
optimization of representative boundary conditions are presented.
The different conditions and inaccuracies both in simulations and
experiments are discussed. The influence of different parameters on
stress and strain distributions is demonstrated on T-joint made of
CFRP (carbon fibre reinforced plastic). A special test rig designed by
VZLU (Aerospace Research and Test Establishment) for T-shear test
procedure is presented.
Abstract: This paper considers the characterization of a complex
electromagnetic environment due to multiple sources of
electromagnetic radiation as a five-dimensional surface which can be
described by a set of several surface sections including: instant EM
field intensity distribution maps at a given frequency and altitude,
instantaneous spectrum at a given location in space and the time
evolution of the electromagnetic field spectrum at a given point in
space. This characterization if done over time can enable the
exposure levels of Radio Frequency Radiation at every point in the
analysis area to be determined and results interpreted based on
comparison of the determined RFR exposure level with the safe
guidelines for general public exposure given by recognized body
such as the International commission on non-ionizing radiation
protection (ICNIRP), Institute of Electrical and Electronic Engineers
(IEEE), the National Radiation Protection Authority (NRPA).
Abstract: In this paper the effect of wall waviness of side walls
in a two-dimensional wavy enclosure is numerically investigated.
Two vertical wavy walls and straight top wall are kept isothermal and
the bottom wall temperature is higher and spatially varying with
cosinusoidal temperature distribution. A computational code based on
Finite-volume approach is used to solve governing equations and
SIMPLE method is used for pressure velocity coupling. Test is
performed for several different numbers of undulations. The Prandtl
number was kept constant and the Ra number denotes that the flow is
laminar. Temperature and velocity fields are determined. Therefore,
according to the obtained results a correlation is proposed for average
Nusselt number as a function of number of side wall waves. The
results indicate that the Nusselt number is highly affected by number
of waves and increasing it decreases the wavy walls Nusselt number;
although the Nusselt number is not highly affected by surface
waviness when the number of undulations is below one.