Abstract: In this paper family of multilevel inverter topology
with reduced number of power switches is presented. The proposed
inverter can generate both even and odd level. The proposed topology
is suitable for symmetric structure. The proposed symmetric inverter
results in reduction of power switches, power diode and gate driver
circuits and also it may further minimize the installation area and
cost. To prove the superiority of proposed topology is compared with
conventional topologies. The performance of this symmetric
multilevel inverter has been tested by computer based simulation and
prototype based experimental setup for nine-level inverter is
developed and results are verified.
Abstract: Due to the advancement of Internet technology, online
learning is widely used in higher education institutions. Online
learning offers several means of communication, including online
forum. Through online forum, students and instructors are able to
discuss and share their knowledge and expertise without having a
need to attend the face-to-face, ordinary classroom session. The
purposes of this study are to analyze the students’ levels of
participation and critical thinking, types of action and factors
influencing their participation in online forum. A total of 41
postgraduate students undertaking a course in educational technology
from a public university in Malaysia were involved in this study. In
this course, the students participated in a weekly online forum as part
of the course requirement. Based on the log data file extracted from
the online forum, the students’ type of actions (view, add, update,
delete posts) and their levels of participation (passive, moderate or
active) were identified. In addition, the messages posted in the forum
were analyzed to gauge their level of critical thinking. Meanwhile,
the factors that might influence their online forum participation were
measured using a 24-items questionnaire. Based on the log data, a
total of 105 posts were sent by the participants. In addition, the
findings show that (i) majority of the students are moderate
participants, with an average of two to three posts per person, (ii)
viewing posts are the most frequent type of action (85.1%), and
followed by adding post (9.7%). Furthermore, based on the posts
they made, the most frequent type of critical thinking observed was
justification (50 input or 19.0%), followed by linking ideas and
interpretation (47 input or 18%), and novelty (38 input or 14.4%).
The findings indicate that online forum allows for social interaction
and can be used to measure the students’ critical thinking skills. In
order to achieve this, monitoring students’ activities in the online
forum is recommended.
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: Lately, asynchronous discussion forum is integrated in
higher educational institutions as it may increase learning process,
learners’ understanding, achievement and knowledge construction.
The asynchronous discussion forum is used to complement the
traditional, face-to-face learning session in hybrid learning courses.
However, studies have proven that students’ engagement in online
forums is still unconvincing. Thus, the aim of this study is to
investigate the motivating factors and obstacles that affect the
learners’ engagement in asynchronous discussion forum. This study
is carried out in one of the public higher educational institutions in
Malaysia with 18 postgraduate students as samples. The authors have
developed a 40-items questionnaire based on literature review. The
results indicate several factors that have encouraged or limited
students’ engagement in asynchronous discussion forum: (a) the
practices or behaviors of peers, or instructors, (b) the needs for the
discussions, (c) the learners’ personalities, (d) constraints in
continuing the discussion forum, (e) lack of ideas, (f) the level of
thoughts, (g) the level of knowledge construction, (h) technical
problems, (i) time constraints and (j) misunderstanding. This study
suggests some recommendations to increase the students’
engagement in online forums. Finally, based upon the findings, some
implications are proposed for further research.
Abstract: This experimental study aims at studying the
conversion of macro-algae into bioethanol under several steps of
procedure: preparation, pre-treatment, fermentation, and distillation.
The main objective of this work was to investigate the role of buffer’s
type as a stabiliser of pH level and fermentation time on the yield of
ethanol. For this purpose, experiments were carried out on biomass
macro-algae to de-couple the pre-treatment and fermentation
processes from those associated with distillation process. β-
glucosidase was used as cellulose decomposer during hydrolysis step
and yeast was used during fermentation process. The species of
macro-algae utilised as energy feedstock was Ulva lactuca and it was
harvested from southern coast of Central of Java Island – Indonesia.
Experiments were conducted in a simple fermenter over a different
buffer: citrate buffer and acetic buffer, and over a range of
fermentation times between 5 to 20 days. The ethanol production was
found to be significantly affected by both variables. The optimum
time of fermentation was 10 days with citrate buffer; result in
0.88458% of ethanol, and the ethanol content after distillation
process was shown 0.985015%.
Abstract: Climate change will affect various aspects of
hydrological cycle such as rainfall. A change in rainfall will affect
flood magnitude and frequency in future which will affect the design
and operation of hydraulic structures. In this paper, trends in subhourly,
sub-daily, and daily extreme rainfall events from 18 rainfall
stations located in Tasmania, Australia are examined. Two nonparametric
tests (Mann-Kendall and Spearman’s Rho) are applied to
detect trends at 10%, 5%, and 1% significance levels. Sub-hourly (6,
12, 18, and 30 minutes) annual maximum rainfall events have been
found to experience statistically significant upward trends at 10%
level of significance. However, sub-daily durations (1 hour, 3 and 12
hours) exhibit decreasing trends and no trends exists for longer
duration rainfall events (e.g. 24 and 72 hours). Some of the durations
(e.g. 6 minutes and 6 hours) show similar results (with upward
trends) for both the tests. For 12, 18, 60 minutes and 3 hours
durations both the tests show similar downward trends. This finding
has important implication for Tasmania in the design of urban
infrastructure where shorter duration rainfall events are more relevant
for smaller urban catchments such as parking lots, roof catchments
and smaller sub-divisions.
Abstract: This study discovers a novel framework of individual
level technology adoption known as I-P (Individual- Privacy) towards
health information application in Smart National Identity Card. Many
countries introduced smart national identity card (SNIC) with various
applications such as health information application embedded inside
it. However, the degree to which citizens accept and use some of the
embedded applications in smart national identity remains unknown to
many governments and application providers as well. Moreover, the
factors of trust, perceived risk, Privacy concern and perceived
credibility need to be incorporated into more comprehensive models
such as extended Unified Theory of Acceptance and Use of
Technology known as UTAUT2. UTAUT2 is a mainly widespread
and leading theory up to now. This research identifies factors
affecting the citizens’ behavioural intention to use health information
application embedded in SNIC and extends better understanding on
the relevant factors that the government and the application providers
would need to consider in predicting citizens’ new technology
acceptance in the future. We propose a conceptual framework by
combining the UTAUT2 and Privacy Calculus Model constructs and
also adding perceived credibility as a new variable. The proposed
framework may provide assistance to any government planning,
decision, and policy makers involving e-government projects.
Empirical study may be conducted in the future to provide proof and
empirically validate this I-P framework.
Abstract: Multiwall carbon nanotubes, prepared by chemical
vapor deposition, have an average diameter of 60-100 nm as shown
by High Resolution Transmittance Electron Microscope, HR-TEM.
The Multiwall carbon nanotubes (MWCNTs) were further
characterized using X-ray Diffraction and Raman Spectroscopy.
Mercury uptake capacity of MWCNTs was studied using batch
adsorption method at different concentration ranges up to 150 ppm.
Mercury concentration (before and after the treatment) was measured
using cold vapor atomic absorption spectroscopy. The effect of time,
concentration, pH and adsorbent dose were studied. MWCNT were
found to perform complete absorption in the sub-ppm concentrations
(parts per billion levels) while for high concentrations, the adsorption
efficiency was 92% at the optimum conditions; 0.1 g of the adsorbent
at 150 ppm mercury (II) solution. The adsorption of mercury on
MWCNTs was found to follow the Freundlich adsorption isotherm
and the pseudo-second order kinetic model.
Abstract: Natural gas, as one of the most important sources of
energy for many of the industrial and domestic users all over the
world, has a complex, huge supply chain which is in need of heavy
investments in all the phases of exploration, extraction, production,
transportation, storage and distribution. The main purpose of supply
chain is to meet customers’ need efficiently and with minimum cost.
In this study, with the aim of minimizing economic costs, different
levels of natural gas supply chain in the form of a multi-echelon,
multi-period fuzzy linear programming have been modeled. In this
model, different constraints including constraints on demand
satisfaction, capacity, input/output balance and presence/absence of a
path have been defined. The obtained results suggest efficiency of the
recommended model in optimal allocation and reduction of supply
chain costs.
Abstract: The purpose of this project is to carry out an analysis
and determine the profile of actual lean manufacturing processes in
the Metropolitan Area of Bucaramanga. Through the analysis of
qualitative and quantitative variables it was possible to establish how
these manufacturers develop production practices that ensure their
competitiveness and productivity in the market.
In this study, a random sample of metallurgic and wrought iron
companies was applied, following which a quantitative focus and
analysis was used to formulate a qualitative methodology for
measuring the level of lean manufacturing procedures in the industry.
A qualitative evaluation was also carried out through a multivariate
analysis using the Numerical Taxonomy System (NTSYS) program
which should allow for the determination of Lean Manufacturing
profiles.
Through the results it was possible to observe how the companies
in the sector are doing with respect to Lean Manufacturing Practices,
as well as identify the level of management that these companies
practice with respect to this topic. In addition, it was possible to
ascertain that there is no one dominant profile in the sector when it
comes to Lean Manufacturing.
It was established that the companies in the metallurgic and
wrought iron industry show low levels of Lean Manufacturing
implementation. Each one carries out diverse actions that are
insufficient to consolidate a sectoral strategy for developing a
competitive advantage which enables them to tie together a
production strategy.
Abstract: A noble low NOx combustion technology, based on
partial oxidation combustion concept in a fuel rich combustion zone, is
successfully applied in this research. The burner is designed such that
a portion of fuel is heated and pre-vaporized in the furnace then
injected into a fuel rich combustion zone so that a partial oxidation
reaction occurs. The effects of equivalence ratio, thermal load, and
fuel distribution ratio on the emissions of NOx and CO are
experimentally investigated. This newly developed combustion
technology showed very low NOx emission level, about 12 ppm, when
light oil is used as a fuel.
Abstract: This paper presents a real-time visualization technique
and filtering of classified LiDAR point clouds. The visualization is
capable of displaying filtered information organized in layers by the
classification attribute saved within LiDAR datasets. We explain the
used data structure and data management, which enables real-time
presentation of layered LiDAR data. Real-time visualization is
achieved with LOD optimization based on the distance from the
observer without loss of quality. The filtering process is done in two
steps and is entirely executed on the GPU and implemented using
programmable shaders.
Abstract: In this paper, snow samples containing dust particles
from several sampling points around the city of Ostrava were
analyzed. The pH values of sampled snow were measured and solid
particles analyzed. Particle size, zeta potential and content of selected
heavy metals were determined in solid particles. The pH values of
most samples lay in the slightly acid region. Mean values of particle
size ranged from 290.5 to 620.5 nm. Zeta potential values varied
between -5 and -26.5 mV. The following heavy metal concentration
ranges were found: copper 0.08-0.75 mg/g, lead 0.05-0.9 mg/g,
manganese 0.45-5.9 mg/g and iron 25.7-280.46 mg/g. The highest
values of copper and lead were found in the vicinity of busy
crossroads, and on the contrary, the highest levels of manganese and
iron were detected close to a large steelworks. The proportion
between pH values, zeta potentials, particle sizes and heavy metal
contents was established. Zeta potential decreased with rising pH
values and, simultaneously, heavy metal content in solid particles
increased. At the same time, higher metal content corresponded to
lower particle size.
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: 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: 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, design of solid-state battery/supercapacitor emulator based on dc-dc boost converter is described.
The emulator mimics charging behavior of any storage device based
on a predefined behavior set by the user. The device is operated by a
two-level control structure: high-level emulating controller and low-
level input voltage controller. Simulation and experimental results are
shown to demonstrate the emulator operation.
Abstract: The goal of this article is the analysis of knowledge
transfer at the regional level of the Czech Republic. We show how
goals of enterprises´ innovative activities are related to the rate of
cooperation with different actors within regional innovative systems
as well as in other world regions. The results show that the most
important partners of enterprises are their suppliers and clients in
most Czech regions. The cooperation rate of enterprises correlates
significantly mainly with enterprises´ efforts to enter new markets
and reduce labour costs per unit output. The meaning of this
cooperation decreases with the increase of partner’s distance.
Regarding the type of a cooperating partner, cooperation within an
enterprise had to do with the increase of market share and decrease of
labour costs. On the other hand, cooperation with clients had to do
with efforts to replace outdated products or processes or enter new
markets. We can pay less attention to the cooperation with
government authorities and organizations. The reasons for
marginalization of this cooperation should be submitted to further
detailed investigation.
Abstract: The use of IT equipment has become a part of every
day. However, each device that is part of cyberspace should be
secured against unauthorized use. It is very important to know the
basics of these security devices, but also the basics of safe conduct
their owners. This information should be part of every curriculum
computer science education in primary and secondary schools.
Therefore, the work focuses on the education of pupils in primary and
secondary schools on the Internet. Analysis of the current state
describes approaches to the education of pupils in security issues on
the Internet. The paper presents a questionnaire-based survey which
was carried out in the Czech Republic, whose task was to ascertain
the level of opinion pupils in primary and secondary schools on the
issue of communication in social networks. The research showed that
awareness of socio-pathological phenomena on the Internet
environment is very low. Based on the results it was proposed
appropriate ways of teaching to this issue and its inclusion a proposal
of curriculum for primary and secondary schools.