Abstract: Device-to-device (D2D) communication is considered a
promising technique to provide wireless peer-to-peer communication
services. Due to increasing demand on mobile services, available
spectrum for radio frequency (RF) based communications becomes
scarce. Recently, visible light communications (VLC) has evolved
as a high speed wireless data transmission technology for indoor
environments with abundant available bandwidth. In this paper,
a novel VLC based D2D communication that provides wireless
peer-to-peer communication is proposed. Potential low operating
power devices for an efficient D2D communication over increasing
distance of separation between devices is analyzed. Optical repeaters
(OR) are also proposed to enhance the performance in an environment
where direct D2D communications yield degraded performance.
Simulation results show that VLC plays an important role in
providing efficient D2D communication up to a distance of 1 m
between devices. It is also found that the OR significantly improves
the coverage distance up to 3.5 m.
Abstract: In this paper, a desiccant solar unit for air
conditioning and desalination is presented first. Secondly, a dynamic
modelling study of the desiccant wheel is developed. After that, a
simulation study and an experimental investigation of the behaviour
of desiccant wheel are developed. The experimental investigation is
done in the chamber of commerce in Freiburg-Germany. Indeed, the
variations of calculated and measured temperatures and specific
humidity of dehumidified and rejected air are presented where a good
agreement is found when comparing the model predictions with
experimental data under the considered range of operating conditions.
Finally, the study of the compartments of desalination and water
condensation shows that the unit can produce an acceptable quantity
of water at the same time of the air conditioning operation.
Abstract: This research provides a technical account of
estimating Transition Probability using Time-homogeneous Markov
Jump Process applying by South African HIV/AIDS data from the
Statistics South Africa. It employs Maximum Likelihood Estimator
(MLE) model to explore the possible influence of Transition
Probability of mortality cases in which case the data was based on
actual Statistics South Africa. This was conducted via an integrated
demographic and epidemiological model of South African HIV/AIDS
epidemic. The model was fitted to age-specific HIV prevalence data
and recorded death data using MLE model. Though the previous
model results suggest HIV in South Africa has declined and AIDS
mortality rates have declined since 2002 – 2013, in contrast, our
results differ evidently with the generally accepted HIV models
(Spectrum/EPP and ASSA2008) in South Africa. However, there is
the need for supplementary research to be conducted to enhance the
demographic parameters in the model and as well apply it to each of
the nine (9) provinces of South Africa.
Abstract: The Flexible AC Transmission System (FACTS)
technology is a new advanced solution that increases the reliability
and provides more flexibility, controllability, and stability of a power
system. The Unified Power Flow Controller (UPFC), as the most
versatile FACTS device for regulating power flow, is able to control
respectively transmission line real power, reactive power, and node
voltage. The main purpose of this paper is to analyze the effect of the
UPFC on the load flow, the power losses, and the voltage stability
using NEPLAN software modules, Newton-Raphson load flow is
used for the power flow analysis and the modal analysis is used for
the study of the voltage stability. The simulation was carried out on
the IEEE 14-bus test system.
Abstract: Microstructure and fabric of soils play an important
role on structural properties e.g. stiffness and strength of compacted
earthwork. Traditional quality control monitoring based on moisturedensity
tests neither reflects the variability of soil microstructure nor
provides a direct assessment of structural property, which is the
ultimate objective of the earthwork quality control. Since stiffness
and strength are sensitive to soil microstructure and fabric, any
independent test methods that provide simple, rapid, and direct
measurement of stiffness and strength are anticipated to provide an
effective assessment of compacted earthen materials’ uniformity. In
this study, the soil stiffness gauge (SSG) and the dynamic cone
penetrometer (DCP) were respectively utilized to measure and
monitor the stiffness and strength in companion with traditional
moisture-density measurements of various earthen materials used in
Thailand road construction projects. The practical earthwork quality
control criteria are presented herein in order to assure proper
earthwork quality control and uniform structural property of
compacted earthworks.
Abstract: Community living adjacent to forests and Protected
Areas, especially in South Asian countries, have a common practice
in extracting resources for their living and livelihoods. This
extraction of resources, because the way it is done, destroys the biophysical
features of the area. Deforestation, wildlife poaching, illegal
logging, unauthorized hill cutting etc. are some of the serious issues
of concern for the sustainability of the natural resources that has a
direct impact on environment and climate as a whole. To ensure
community involvement in conservation initiatives of the state,
community based forest management, commonly known as Comanagement,
has been in practice in 6 South Asian countries. These
are -India, Nepal, Sri Lanka, Pakistan, Bhutan and Bangladesh.
Involving community in forestry management was initiated first in
Bangladesh in 1979 and reached as an effective co-management
approach through a several paradigm shifts. This idea of Comanagement
has been institutionalized through a Government Order
(GO) by the Ministry of Environment and Forests, Government of
Bangladesh on November 23, 2009. This GO clearly defines the
structure and functions of Co-management and its different bodies.
Bangladesh Forest Department has been working in association with
community to conserve and manage the Forests and Protected areas
of Bangladesh following this legal document. Demographically
young people constitute the largest segment of population in
Bangladesh. This group, if properly sensitized, can produce valuable
impacts on the conservation initiatives, both by community and
government. This study traced the major factors that motivate
community youths to work effectively with different tiers of comanagement
organizations in conservation of forests and Protected
Areas of Bangladesh. For the purpose of this study, 3 FGDs were
conducted with 30 youths from the community living around the
Protected Areas of Cox’s bazar, South East corner of Bangladesh,
who are actively involved in Co-management organizations. KII were
conducted with 5 key officials of Forest Department stationed at
Cox’s Bazar. 2 FGDs were conducted with the representatives of 7
Co-management organizations working in Cox’s Bazar region and
approaches of different community outreach activities conducted for
forest conservation by 3 private organizations and Projects have been
reviewed. Also secondary literatures were reviewed for the history
and evolution of Co-management in Bangladesh and six South Asian
countries. This study found that innovative community outreach
activities that are financed by public and private sectors involving
youths and community as a whole have played a pivotal role in
conservation of forests and Protected Areas of the region. This
approach can be replicated in other regions of Bangladesh as well as
other countries of South Asia where Co-Management exists in
practice.
Abstract: Solar water heating is a thermodynamic process of
heating water using sunlight with the help of solar water heater. Thus,
solar water heater is a device used to harness solar energy. In this
paper, a modified solar water heating system (MSWHS) has been
proposed over flat plate collector (FPC) and Evacuated tube collector
(ETC). The modifications include selection of materials other than
glass, and glass wool which are conventionally used for fabricating
FPC and ETC. Some modifications in design have also been
proposed. Its collector is made of double layer of semi-cylindrical
acrylic tubes and fibre reinforced plastic (FRP) insulation base. Water
tank is made of double layer of acrylic sheet except base and north
wall. FRP is used in base and north wall of the water tank. A concept
of equivalent thickness has been utilised for calculating the
dimensions of collector plate, acrylic tube and tank. A thermal model for the proposed design of MSWHS is developed
and simulation is carried out on MATLAB for the capacity of 200L
MSWHS having collector area of 1.6 m2, length of acrylic tubes of
2m at an inclination angle 25° which is taken nearly equal to the
latitude of the given location. Latitude of Allahabad is 24.45° N. The
results show that the maximum temperature of water in tank and tube
has been found to be 71.2°C and 73.3°C at 17:00hr and 16:00hr
respectively in March for the climatic data of Allahabad. Theoretical performance analysis has been carried out by varying
number of tubes of collector, the tank capacity and climatic data for
given months of winter and summer.
Abstract: The rapid growth of the human population and the
environmental degradation associated with increased consumption of
resources raises concerns on sustainability. Social sustainability
constitutes one of the three dimensions of sustainability together with
environmental and economic dimensions. Even though there is not an
agreement on what social sustainability consists of, it is a well known
fact that it necessitates user participation. The fore, this study aims to
observe and analyze the role of user participation on social
sustainability. In this paper, the links between user participation and indicators of
social sustainability have been searched. In order to achieve this, first
of all a literature review on social sustainability has been done;
accordingly, the information obtained from researches has been used
in the evaluation of the projects conducted in the developing
countries considering user participation. These examples are taken as
role models with pros and cons for the development of the checklist
for the evaluation of the case studies. Furthermore, a case study over
the post earthquake residential settlements in Turkey have been
conducted. The case study projects are selected considering different building
scales (differing number of residential units), scale of the problem
(post-earthquake settlements, rehabilitation of shanty dwellings) and
the variety of users (differing socio-economic dimensions). Decisionmaking,
design, building and usage processes of the selected projects
and actors of these processes have been investigated in the context of
social sustainability. The cases include: New Gourna Village by
Hassan Fathy, Quinta Monroy dwelling units conducted in Chile by
Alejandro Aravena and Beyköy and Beriköy projects in Turkey
aiming to solve the problem of housing which have appeared after the
earthquake happened in 1999 have been investigated. Results of the
study possible links between social sustainability indicators and user
participation and links between user participation and the
peculiarities of place. Results are compared and discussed in order to find possible
solutions to form social sustainability through user participation.
Results show that social sustainability issues depend on communities'
characteristics, socio-economic conditions and user profile but user
participation has positive effects on some social sustainability
indicators like user satisfaction, a sense of belonging and social
stability.
Abstract: The exploitation of flow pulsation in micro- and
mini-channels is a potentially useful technique for enhancing cooling
of high-end photonics and electronics systems. It is thought that
pulsation alters the thickness of the hydrodynamic and thermal
boundary layers, and hence affects the overall thermal resistance
of the heat sink. Although the fluid mechanics and heat transfer
are inextricably linked, it can be useful to decouple the parameters
to better understand the mechanisms underlying any heat transfer
enhancement. Using two-dimensional, two-component particle image
velocimetry, the current work intends to characterize the heat transfer
mechanisms in pulsating flow with a mean Reynolds number of
48 by experimentally quantifying the hydrodynamics of a generic
liquid-cooled channel geometry. Flows circulated through the test
section by a gear pump are modulated using a controller to achieve
sinusoidal flow pulsations with Womersley numbers of 7.45 and
2.36 and an amplitude ratio of 0.75. It is found that the transient
characteristics of the measured velocity profiles are dependent on the
speed of oscillation, in accordance with the analytical solution for
flow in a rectangular channel. A large velocity overshoot is observed
close to the wall at high frequencies, resulting from the interaction
of near-wall viscous stresses and inertial effects of the main fluid
body. The steep velocity gradients at the wall are indicative of
augmented heat transfer, although the local flow reversal may reduce
the upstream temperature difference in heat transfer applications.
While unsteady effects remain evident at the lower frequency, the
annular effect subsides and retreats from the wall. The shear rate at
the wall is increased during the accelerating half-cycle and decreased
during deceleration compared to steady flow, suggesting that the flow
may experience both enhanced and diminished heat transfer during
a single period. Hence, the thickness of the hydrodynamic boundary
layer is reduced for positively moving flow during one half of the
pulsation cycle at the investigated frequencies. It is expected that the
size of the thermal boundary layer is similarly reduced during the
cycle, leading to intervals of heat transfer enhancement.
Abstract: In general, it is desirable to finish the weld quickly,
before a large volume of surrounding metal heats up and expands.
The welding process used, type, welding current and speed of travel,
thus, affect the degree of shrinkage and distortion of a weldment. The
use of mechanized welding equipment reduces welding time, metal
affected zone and consequently distortion. This article helps to define
what weld distortion is and then provide a practical understanding of
the causes of distortion, effects of shrinkage in butt joint welded
assemblies using TI6AL4VA and Aluminium AA2024 alloy sheet.
The beam offset position to the joint interface towards titanium and
aluminium side. The factors affecting distortion during welding is
also given. Test results reveal that welding speed is the significant
parameter to decide the extent of distortion. Also welding from Al
side reduces the distortion while Ti side increases the distortion.
Abstract: In this paper, we present the design of the
super-ellipsoidal potential function (SEPF), that can be used for
autonomous collision avoidance of an unmanned aerial vehicle (UAV)
in a 3-dimensional space. In the design of SEPF, we have the
full control over the shape and size of the potential function. In
particular, we can adjust the length, width, height, and the amount
of flattening at the tips of the potential function so that the collision
avoidance motion vector generated from the potential function can
be adjusted accordingly. Based on the idea of the SEPF, we also
propose an approach for the local autonomy of a UAV for its collision
avoidance when the UAV is teleoperated by a human operator. In
our proposed approach, a teleoperated UAV can not only avoid
collision autonomously with other surrounding objects but also track
the operator’s control input as closely as possible. As a result, an
operator can always be in control of the UAV for his/her high-level
guidance and navigation task without worrying too much about
the UAVs collision avoidance while it is being teleoperated. The
effectiveness of the proposed approach is demonstrated through a
human-in-the-loop simulation of quadrotor UAV teleoperation using
virtual robot experimentation platform (v-rep) and Matlab programs.
Abstract: This paper discusses the intake of combining multi-criteria
decision analysis (MCDA) with OLAP systems, to generate
an integrated analysis process dealing with complex multi-criteria
decision-making situations. In this context, a multi-agent modeling is
presented for decision support systems by combining multi-criteria
decision analysis (MCDA) with OLAP systems. The proposed
modeling which consists in performing the multi-agent system
(MAS) architecture, procedure and protocol of the negotiation model
is elaborated as a decision support tool for complex decision-making
environments. Our objective is to take advantage from the multi-agent
system which distributes resources and computational
capabilities across interconnected agents, and provide a problem
modeling in terms of autonomous interacting component-agents.
Thus, the identification and evaluation of criteria as well as the
evaluation and ranking of alternatives in a decision support situation
will be performed by organizing tasks and user preferences between
different agents in order to reach the right decision. At the end, an
illustrative example is conducted to demonstrate the function and
effectiveness of our MAS modeling.
Abstract: Reinforced earth structures are generally subjected to cyclic loading generated from earthquakes. This paper presents a summary of the results and analyses of a testing program carried out in a large-scale multi-function geosynthetic testing apparatus that accommodates soil samples up to 1.0 m3. This apparatus performs different shear and pullout tests under both static and cyclic loading. The testing program was carried out to investigate the controlling factors affecting soil/geogrid interaction under cyclic loading. The extensibility of the geogrids, the applied normal stresses, the characteristics of the cyclic loading (frequency, and amplitude), and initial static load within the geogrid sheet were considered in the testing program. Based on the findings of the testing program, the effect of these parameters on the pullout resistance of geogrids, as well as the displacement mobility under cyclic loading were evaluated. Conclusions and recommendations for the design of reinforced earth walls under cyclic loading are presented.
Abstract: This article describes the implementation of an
experimental model for teaching ICT tools and digital environments
in teachers training college. In most educational systems in the
Western world, new programs were developed in order to bridge the
digital gap between teachers and students. In spite of their
achievements, these programs are limited due to several factors: The
teachers in the schools implement new methods incorporating
technological tools into the curriculum, but meanwhile the
technology changes and advances. The interface of tools changes
frequently, some tools disappear and new ones are invented. These
conditions require an experimental model of training the pre-service
teachers. The appropriate method for instruction within the domain of
ICT tools should be based on exposing the learners to innovations,
helping them to gain experience, teaching them how to deal with
challenges and difficulties on their own, and training them. This
study suggests some principles for this approach and describes step
by step the implementation of this model.
Abstract: The study was meant to identify the impediments to
female sports management and participation in the selected colleges.
Seven colleges of education in the south west parts of the country
were selected for the study. A total of one hundred and five subjects
were sampled to supply data. Only one hundred adequately
completed and returned, copies of the questionnaire were used for
data analysis. The collected data were analysed descriptively. The
result of the study showed that inadequate fund, personnel, facilities
equipment, supplies, management of sports, supervision and coaching
were some of the impediments to female sports management and
participation. Athletes were not encouraged to participate. Based on
the findings, it was recommended that the government should come
to the aid of the colleges by providing fund and other needs that will
make sports attractive for enhanced participation.
Abstract: The power buck converter is the most widely used
DC/DC converter topology. They have a very large application area
such as DC motor drives, photovoltaic power system which require
fast transient responses and high efficiency over a wide range of load
current. This work proposes, the modelling of DC/DC power buck
converter using state-space averaging method and the current-mode
control using a proportional-integral controller. The efficiency of the
proposed model and control loop are evaluated with operating point
changes. The simulation results proved the effectiveness of the linear
model of DC/DC power buck converter.
Abstract: Recent progress in the next generation of automobile
technology is geared towards incorporating information technology
into cars. Collectively called smart cars are bringing intelligence to
cars that provides comfort, convenience and safety. A branch of smart
cars is connected-car system. The key concept in connected-cars is the
sharing of driving information among cars through decentralized
manner enabling collective intelligence. This paper proposes a
foundation of the information model that is necessary to define the
driving information for smart-cars. Road conditions are modeled
through a unique data structure that unambiguously represent the time
variant traffics in the streets. Additionally, the modeled data structure
is exemplified in a navigational scenario and usage using UML.
Optimal driving route searching is also discussed using the proposed
data structure in a dynamically changing road conditions.
Abstract: Cloud computing is a business model which provides
an easier management of computing resources. Cloud users can
request virtual machine and install additional softwares and configure
them if needed. However, user can also request virtual appliance
which provides a better solution to deploy application in much faster
time, as it is ready-built image of operating system with necessary
softwares installed and configured. Large numbers of virtual
appliances are available in different image format. User can
download available appliances from public marketplace and start
using it. However, information published about the virtual appliance
differs from each providers leading to the difficulty in choosing
required virtual appliance as it is composed of specific OS with
standard software version. However, even if user choses the
appliance from respective providers, user doesn’t have any flexibility
to choose their own set of softwares with required OS and
application. In this paper, we propose a referenced architecture for
dynamically customizing virtual appliance and provision them in an
easier manner. We also add our experience in integrating our
proposed architecture with public marketplace and Mi-Cloud, a cloud
management software.
Abstract: Recently developed cooperative diversity scheme
enables a terminal to get transmit diversity through the support of other
terminals. However, most of the introduced cooperative schemes have
a common fault of decreased transmission rate because the destination
should receive the decodable compositions of symbols from the source
and the relay. In order to achieve high data rate, we propose a
cooperative scheme that employs hierarchical modulation. This
scheme is free from the rate loss and allows seamless cooperative
communication.
Abstract: The aim of this research is to understand how the
emerging power bloc BRICS employs infrastructure development
narratives to construct a new world order. BRICS is an international
body consisting of five emerging countries that collaborate on
economic and political issues: Brazil, Russia, India, China, and South
Africa. This study explores the projection of infrastructure
development narratives through an analysis of BRICS’ attention to
infrastructure investment and financing, its support of the New
Partnership on African Development and the establishment of the
New Development Bank in Shanghai. The theory of Strategic
Narratives is used to explore BRICS’ commitment to infrastructure
development and to distinguish three layers: system narratives
(BRICS as a global actor to propose development reform), identity
narratives (BRICS as a collective identity joining efforts to act upon
development aspirations) and issue narratives (BRICS committed to a
range of issues of which infrastructure development is prominent).
The methodology that is employed is a narrative analysis of BRICS’
official documents, media statements, and website imagery. A
comparison of these narratives illuminates tensions at the three layers
and among the five member states. Identifying tensions among
development infrastructure narratives provides an indication of how
policymaking for infrastructure development could be improved.
Subsequently, it advances BRICS’ ability to act as a global actor to
construct a new world order.