Abstract: Nowadays, the use of renewable energy sources has been increasingly great because of the cost increase and public demand for clean energy sources. One of the fastest growing sources is wind energy. In this paper, Wind Diesel Hybrid System (WDHS) comprising a Diesel Generator (DG), a Wind Turbine Generator (WTG), the Consumer Load, a Battery-based Energy Storage System (BESS), and a Dump Load (DL) is used. Voltage is controlled by Diesel Generator; the frequency is controlled by BESS and DL. The BESS elimination is an efficient way to reduce maintenance cost and increase the dynamic response. Simulation results with graphs for the frequency of Power System, active power, and the battery power are presented for load changes. The controlling parameters are optimized by using Imperialist Competitive Algorithm (ICA). The simulation results for the BESS/no BESS cases are compared. Results show that in no BESS case, the frequency control is more optimal than the BESS case by using ICA.
Abstract: PhilSHORE is a multi-site, multi-device and multicriteria
decision support tool designed to support the development of
tidal current energy in the Philippines. Its platform is based on
Geographic Information Systems (GIS) which allows for the
collection, storage, processing, analyses and display of geospatial
data. Combining GIS tools with open source web development
applications, PhilSHORE becomes a webGIS-based marine spatial
planning tool. To date, PhilSHORE displays output maps and graphs
of power and energy density, site suitability and site-device analysis.
It enables stakeholders and the public easy access to the results of
tidal current energy resource assessments and site suitability
analyses. Results of the initial development show that PhilSHORE is
a promising decision support tool for ORE project developments.
Abstract: The eccentric connectivity index based on degree and
eccentricity of the vertices of a graph is a widely used graph invariant
in mathematics.
In this paper, we present the explicit eccentric connectivity index,
first and second Zagreb indices for a Corona graph and sub divisionrelated
corona graphs.
Abstract: This research was conducted in the Mae Sot
Watershed where located in the Moei River Basin at the Upper
Salween River Basin in Tak Province, Thailand. The Mae Sot
Municipality is the largest urban area in Tak Province and situated in
the midstream of the Mae Sot Watershed. It usually faces flash flood
problem after heavy rain due to poor flood management has been
reported since economic rapidly bloom up in recent years. Its
catchment can be classified as ungauged basin with lack of rainfall
data and no any stream gaging station was reported. It was attached
by most severely flood events in 2013 as the worst studied case for
all those communities in this municipality. Moreover, other problems
are also faced in this watershed, such shortage water supply for
domestic consumption and agriculture utilizations including a
deterioration of water quality and landslide as well. The research
aimed to increase capability building and strengthening the
participation of those local community leaders and related agencies to
conduct better water management in urban area was started by mean
of the data collection and illustration of the appropriated application
of some short period rainfall forecasting model as they aim for better
flood relief plan and management through the hydrologic model
system and river analysis system programs. The authors intended to
apply the global rainfall data via the integrated data viewer (IDV)
program from the Unidata with the aim for rainfall forecasting in a
short period of 7-10 days in advance during rainy season instead of
real time record. The IDV product can be present in an advance
period of rainfall with time step of 3-6 hours was introduced to the
communities. The result can be used as input data to the hydrologic
modeling system model (HEC-HMS) for synthesizing flood
hydrographs and use for flood forecasting as well. The authors
applied the river analysis system model (HEC-RAS) to present flood
flow behaviors in the reach of the Mae Sot stream via the downtown
of the Mae Sot City as flood extents as the water surface level at
every cross-sectional profiles of the stream. Both models of HMS and
RAS were tested in 2013 with observed rainfall and inflow-outflow
data from the Mae Sot Dam. The result of HMS showed fit to the
observed data at the dam and applied at upstream boundary discharge
to RAS in order to simulate flood extents and tested in the field, and
the result found satisfying. The product of rainfall from IDV was fair
while compared with observed data. However, it is an appropriate
tool to use in the ungauged catchment to use with flood hydrograph
and river analysis models for future efficient flood relief plan and
management.
Abstract: The number of Ground Motion Prediction Equations
(GMPEs) used for predicting peak ground acceleration (PGA) and
the number of earthquake recordings that have been used for fitting
these equations has increased in the past decades. The current PF-L
database contains 3550 recordings. Since the GMPEs frequently
model the peak ground acceleration the goal of the present study was
to refit a selection of 44 of the existing equation models for PGA in
light of the latest data. The algorithm Levenberg-Marquardt was used
for fitting the coefficients of the equations and the results are
evaluated both quantitatively by presenting the root mean squared
error (RMSE) and qualitatively by drawing graphs of the five best
fitted equations. The RMSE was found to be as low as 0.08 for the
best equation models. The newly estimated coefficients vary from the
values published in the original works.
Abstract: Equal channel angular pressing (ECAP) of
commercial Al-Mg-Si alloy was conducted using two strain rates.
The ECAP processing was conducted at room temperature and at
250°C. Route A was adopted up to a total number of four passes in
the present work. Structural evolution of the aluminum alloy discs
was investigated before and after ECAP processing using optical
microscopy (OM). Following ECAP, simple compression tests and
Vicker’s hardness were performed. OM micrographs showed that, the
average grain size of the as-received Al-Mg-Si disc tends to be larger
than the size of the ECAP processed discs. Moreover, significant
difference in the grain morphologies of the as-received and processed
discs was observed. Intensity of deformation was observed via the
alignment of the Al-Mg-Si consolidated particles (grains) in the
direction of shear, which increased with increasing the number of
passes via ECAP. Increasing the number of passes up to 4 resulted in
increasing the grains aspect ratio up to ~5. It was found that the
pressing temperature has a significant influence on the
microstructure, Hv-values, and compressive strength of the processed
discs. Hardness measurements demonstrated that 1-pass resulted in
increase of Hv-value by 42% compared to that of the as-received
alloy. 4-passes of ECAP processing resulted in additional increase in
the Hv-value. A similar trend was observed for the yield and
compressive strength. Experimental data of the Hv-values
demonstrated that there is a lack of any significant dependence on the
processing strain rate.
Abstract: Given a graph G. A cycle of G is a sequence of
vertices of G such that the first and the last vertices are the same.
A hamiltonian cycle of G is a cycle containing all vertices of G.
The graph G is k-ordered (resp. k-ordered hamiltonian) if for any
sequence of k distinct vertices of G, there exists a cycle (resp.
hamiltonian cycle) in G containing these k vertices in the specified
order. Obviously, any cycle in a graph is 1-ordered, 2-ordered and 3-
ordered. Thus the study of any graph being k-ordered (resp. k-ordered
hamiltonian) always starts with k = 4. Most studies about this topic
work on graphs with no real applications. To our knowledge, the
chordal ring families were the first one utilized as the underlying
topology in interconnection networks and shown to be 4-ordered.
Furthermore, based on our computer experimental results, it was
conjectured that some of them are 4-ordered hamiltonian. In this
paper, we intend to give some possible directions in proving the
conjecture.
Abstract: Two Lithium Disilicate (LD) glass ceramics based on
SiO2-Li2O-K2O-Al2O3 system were prepared through a glass melting
method. The glass rods were then fabricated into dental crowns via a
hot pressing at 900˚C and 850˚C in order to study the effect of the
pressing temperatures on the phase formation and microstructure of
the glasses. Different samples of as cast glass and heat treated
samples (600˚C and 700˚C) were used to press for investigating the
effect of an initial microstructure on the hot pressing technique. Xray
diffraction (XRD) and scanning electron microscopy (SEM) were
performed to determine the phase formation and microstructure of the
samples, respectively. XRD results show that the main crystalline
structure was Li2Si2O5 by having Li3PO4, Li0.6Al0.6Si2O6, Li2SiO3,
Ca5 (PO4)3F and SiO2 as minor phases. Glass compositions with
different heat treatment temperatures exhibited a difference phase
formations but have less effect during pressing. SEM micrographs
showed the microstructure of Li2Si2O5 as lath-like shape in all
glasses. With increasing the initial heat treatment temperature, the
longer the lath-like crystals of lithium disilicate were increased
especially when using glass heat treatment at 700˚C followed by
pressing at 900˚C. This could be suggested that LD1 heat treatment at
700˚C which pressing at 900˚C presented the best formation by the
hot pressing and compiled microstructure.
Abstract: The world wide web network is a network with a
complex topology, the main properties of which are the distribution
of degrees in power law, A low clustering coefficient and a weak
average distance. Modeling the web as a graph allows locating the
information in little time and consequently offering a help in the
construction of the research engine. Here, we present a model based
on the already existing probabilistic graphs with all the aforesaid
characteristics. This work will consist in studying the web in order to
know its structuring thus it will enable us to modelize it more easily
and propose a possible algorithm for its exploration.
Abstract: Ongoing landscape transformation is one of the major
causes behind disappearance of traditional landscapes, and lead to
species and resource loss. Tree in paddy fields in the northeast of
Thailand is one of those traditional landscapes. Using three different
historical time layers, we acknowledged the severe deforestation and
rapid urbanization happened in the region. Despite the general
thinking of decline in tree density as consequences, the heterogeneous
trend of changes in total tree density in three studied landscapes denied
the hypothesis that number of trees in paddy field depend on the length
of land use practice. On the other hand, due to selection of planting
new trees on levees, existence of trees in paddy field now relies on
their values for human use. Besides, changes in land use and landscape
structure had a significant impact on decision of which tree density
level is considered as suitable for the landscape.
Abstract: The emergence of the Semantic Web technology
increases day by day due to the rapid growth of multiple web pages.
Many standard formats are available to store the semantic web data.
The most popular format is the Resource Description Framework
(RDF). Querying large RDF graphs becomes a tedious procedure
with a vast increase in the amount of data. The problem of query
optimization becomes an issue in querying large RDF graphs.
Choosing the best query plan reduces the amount of query execution
time. To address this problem, nature inspired algorithms can be used
as an alternative to the traditional query optimization techniques. In
this research, the optimal query plan is generated by the proposed
SAPSO algorithm which is a hybrid of Simulated Annealing (SA)
and Particle Swarm Optimization (PSO) algorithms. The proposed
SAPSO algorithm has the ability to find the local optimistic result
and it avoids the problem of local minimum. Experiments were
performed on different datasets by changing the number of predicates
and the amount of data. The proposed algorithm gives improved
results compared to existing algorithms in terms of query execution
time.
Abstract: A theoretical study has been presented to describe the boundary layer flow and heat transfer on an exponentially shrinking sheet with a variable wall temperature and suction, in the presence of magnetic field. The governing nonlinear partial differential equations are converted into ordinary differential equations by similarity transformation, which are then solved numerically using the shooting method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented through graphs and tables for several sets of values of the parameters. The effects of the governing parameters on the flow and heat transfer characteristics are thoroughly examined.
Abstract: Flood routing is used in estimating the travel time and attenuation of flood waves as they move downstream a river or channel. The routing procedure is usually classified as hydrologic or hydraulic. Hydraulic methods utilize the equations of continuity and motion. Kinematic routing, a hydraulic technique was used in routing Asa River at Ilorin. The river is of agricultural and industrial importance to Ilorin, the capital of Kwara State, Nigeria. This paper determines the kinematic parameters of kinematic wave velocity, time step, time required to traverse, weighting factor and change in length. Values obtained were 4.67 m/s, 19 secs, 21 secs, 0.75 and 100 m, respectively. These parameters adequately reflect the watershed and flow characteristics essential for the routing. The synthetic unit hydrograph was developed using the Natural Resources Conservation Service (NRCS) method. 24-hr 10yr, 25yr, 50yr and 100yr storm hydrographs were developed from the unit hydrograph using convolution procedures and the outflow hydrographs were obtained for each of 24-hr 10yr, 25yr, 50yr and 100yr indicating 0.11 m3/s, 0.10 m3/s, 0.10 m3/s and 0.10 m3/s attenuations respectively.
Abstract: In this paper, we employ a directed hypergraph model
to investigate the extent to which environmental variability influences
the set of available biochemical reactions within a living cell.
Such an approach avoids the limitations of the usual complex
network formalism by allowing for the multilateral relationships (i.e.
connections involving more than two nodes) that naturally occur
within many biological processes. More specifically, we extend the
concept of network reciprocity to complex hyper-networks, thus
enabling us to characterise a network in terms of the existence
of mutual hyper-connections, which may be considered a proxy
for metabolic network complexity. To demonstrate these ideas, we
study 115 metabolic hyper-networks of bacteria, each of which
can be classified into one of 6 increasingly varied habitats.
In particular, we found that reciprocity increases significantly
with increased environmental variability, supporting the view that
organism adaptability leads to increased complexities in the resultant
biochemical networks.
Abstract: Localization of mobile robots are important tasks for
developing autonomous mobile robots. This paper proposes a method
to estimate positions of a mobile robot using a omnidirectional
camera on the robot. Landmarks for points of references are set
up on a field where the robot works. The omnidirectional camera
which can obtain 360 [deg] around images takes photographs of
these landmarks. The positions of the robots are estimated from
directions of these landmarks that are extracted from the images
by image processing. This method can obtain the robot positions
without accumulative position errors. Accuracy of the estimated
robot positions by the proposed method are evaluated through some
experiments. The results show that it can obtain the positions with
small standard deviations. Therefore the method has possibilities of
more accurate localization by tuning of appropriate offset parameters.
Abstract: This paper presents the use of phasor bond graphs to
obtain the steady-state behavior of a synchronous generator. The
phasor bond graph elements are built using 2D multibonds, which
represent the real and imaginary part of the phasor. The dynamic
bond graph model of a salient-pole synchronous generator is showed,
and verified viz. a sudden short-circuit test. The reduction of the
dynamic model into a phasor representation is described. The
previous test is executed on the phasor bond graph model, and its
steady-state values are compared with the dynamic response. Besides,
the widely used power (torque)-angle curves are obtained by means
of the phasor bond graph model, to test the usefulness of this model.
Abstract: This paper proposes a phasor representation of
electrical networks by using bond graph methodology. A so-called
phasor bond graph is built up by means of two-dimensional bonds,
which represent the complex plane. Impedances or admittances are
used instead of the standard bond graph elements. A procedure to
obtain the steady-state values from a phasor bond graph model is
presented. Besides the presentation of a phasor bond graph library in
SIDOPS code, also an application example is discussed.
Abstract: In a perfect secret-sharing scheme, a dealer distributes
a secret among a set of participants in such a way that only qualified
subsets of participants can recover the secret and the joint share of the
participants in any unqualified subset is statistically independent of
the secret. The access structure of the scheme refers to the collection
of all qualified subsets. In a graph-based access structures, each vertex
of a graph G represents a participant and each edge of G represents a
minimal qualified subset. The average information ratio of a perfect
secret-sharing scheme realizing a given access structure is the ratio
of the average length of the shares given to the participants to the
length of the secret. The infimum of the average information ratio
of all possible perfect secret-sharing schemes realizing an access
structure is called the optimal average information ratio of that access
structure. We study the optimal average information ratio of the
access structures based on bipartite graphs. Based on some previous
results, we give a bound on the optimal average information ratio
for all bipartite graphs of girth at least six. This bound is the best
possible for some classes of bipartite graphs using our approach.
Abstract: In this paper, we have investigated the free convection MHD flow due to heat and mass transfer through porous medium bounded by an infinite vertical non-conducting porous plate with time dependent suction under the influence of uniform transverse magnetic field of strength H0. When Temperature (T) and Concentration (C) at the plate is oscillatory with time about a constant non-zero mean. The velocity distribution, the temperature distribution, co-efficient of skin friction and role of heat transfer is investigated. Here the partial differential equations are involved. Exact solution is not possible so approximate solution is obtained and various graphs are plotted.