Abstract: In this study, we propose a novel technique for acoustic
echo suppression (AES) during speech recognition under barge-in
conditions. Conventional AES methods based on spectral subtraction
apply fixed weights to the estimated echo path transfer function
(EPTF) at the current signal segment and to the EPTF estimated until
the previous time interval. However, the effects of echo path changes
should be considered for eliminating the undesired echoes. We
describe a new approach that adaptively updates weight parameters in
response to abrupt changes in the acoustic environment due to
background noises or double-talk. Furthermore, we devised a voice
activity detector and an initial time-delay estimator for barge-in speech
recognition in communication networks. The initial time delay is
estimated using log-spectral distance measure, as well as
cross-correlation coefficients. The experimental results show that the
developed techniques can be successfully applied in barge-in speech
recognition systems.
Abstract: Electric vehicles are one of the most complicated
electric devices to simulate due to the significant number of different
processes involved in electrical structure of it. There are concurrent
processes of energy consumption and generation with different
onboard systems, which make simulation tasks more complicated to
perform. More accurate simulation on energy consumption can
provide a better understanding of all energy management for electric
transport. As a result of all those processes, electric transport can
allow for a more sustainable future and become more convenient in
relation to the distance range and recharging time. This paper
discusses the problems of energy consumption simulations for
electric vehicles using different software packages to provide ideas
on how to make this process more precise, which can help engineers
create better energy management strategies for electric vehicles.
Abstract: Environmental impacts of six 3D printers using
various materials were compared to determine if material choice
drove sustainability, or if other factors such as machine type, machine
size, or machine utilization dominate. Cradle-to-grave life-cycle
assessments were performed, comparing a commercial-scale FDM
machine printing in ABS plastic, a desktop FDM machine printing in
ABS, a desktop FDM machine printing in PET and PLA plastics, a
polyjet machine printing in its proprietary polymer, an SLA machine
printing in its polymer, and an inkjet machine hacked to print in salt
and dextrose. All scenarios were scored using ReCiPe Endpoint H
methodology to combine multiple impact categories, comparing
environmental impacts per part made for several scenarios per
machine. Results showed that most printers’ ecological impacts were
dominated by electricity use, not materials, and the changes in
electricity use due to different plastics was not significant compared
to variation from one machine to another. Variation in machine idle
time determined impacts per part most strongly. However, material
impacts were quite important for the inkjet printer hacked to print in
salt: In its optimal scenario, it had up to 1/38th the impacts coreper
part as the worst-performing machine in the same scenario. If salt
parts were infused with epoxy to make them more physically robust,
then much of this advantage disappeared, and material impacts
actually dominated or equaled electricity use. Future studies should
also measure DMLS and SLS processes / materials.
Abstract: One of the major difficulties introduced with wind
power penetration is the inherent uncertainty in production originating
from uncertain wind conditions. This uncertainty impacts many
different aspects of power system operation, especially the balancing
power requirements. For this reason, in power system development
planing, it is necessary to evaluate the potential uncertainty in future
wind power generation. For this purpose, simulation models are
required, reproducing the performance of wind power forecasts.
This paper presents a wind power forecast error simulation models
which are based on the stochastic process simulation. Proposed
models capture the most important statistical parameters recognized
in wind power forecast error time series. Furthermore, two distinct
models are presented based on data availability. First model uses
wind speed measurements on potential or existing wind power plant
locations, while the seconds model uses statistical distribution of wind
speeds.
Abstract: Alkylated silicon nanocrystals (C11-SiNCs) were
prepared successfully by galvanostatic etching of p-Si(100) wafers
followed by a thermal hydrosilation reaction of 1-undecene in
refluxing toluene in order to extract C11-SiNCs from porous silicon.
Erbium trichloride was added to alkylated SiNCs using a simple
mixing chemical route. To the best of our knowledge, this is the first
investigation on mixing SiNCs with erbium ions (III) by this
chemical method. The chemical characterization of C11-SiNCs and
their mixtures with Er3+(Er/C11-SiNCs) were carried out using X-ray
photoemission spectroscopy (XPS). The optical properties of C11-
SiNCs and their mixtures with Er3+ were investigated using Raman
spectroscopy and photoluminescence (PL). The erbium mixed
alkylated SiNCs shows an orange PL emission peak at around 595
nm that originates from radiative recombination of Si. Er/C11-SiNCs
mixture also exhibits a weak PL emission peak at 1536 nm that
originates from the intra-4f transition in erbium ions (Er3+). The PL
peak of Si in Er/C11-SiNCs mixture is increased in the intensity up to
three times as compared to pure C11-SiNCs. The collected data
suggest that this chemical mixing route leads instead to a transfer of
energy from erbium ions to alkylated SiNCs.
Abstract: Modular structural systems are constructed using a
method that they are assembled with prefabricated unit modular
frames on-site. This provides a benefit that can significantly reduce
building construction time. The structural design is usually carried out
under the assumption that their load-carrying mechanism is similar to
that of traditional steel moment-resisting systems. However, both
systems are different in terms of beam-column connection details
which may strongly influence the lateral structural behavior. Specially,
the presence of access holes in a beam-column joint of a unit modular
frame could cause undesirable failure during strong earthquakes.
Therefore, this study carried out finite element analyses (FEMs) of
unit modular frames to investigate the cyclic behavior of beam-column
joints with the access holes. Analysis results show that the unit
modular frames present stable cyclic response with large deformation
capacities and their joints are classified into semi-rigid connections
even if there are access holes.
Abstract: We have developed a new computer program in
Fortran 90, in order to obtain numerical solutions of a system
of Relativistic Magnetohydrodynamics partial differential equations
with predetermined gravitation (GRMHD), capable of simulating
the formation of relativistic jets from the accretion disk of matter
up to his ejection. Initially we carried out a study on numerical
methods of unidimensional Finite Volume, namely Lax-Friedrichs,
Lax-Wendroff, Nessyahu-Tadmor method and Godunov methods
dependent on Riemann problems, applied to equations Euler in
order to verify their main features and make comparisons among
those methods. It was then implemented the method of Finite
Volume Centered of Nessyahu-Tadmor, a numerical schemes that
has a formulation free and without dimensional separation of
Riemann problem solvers, even in two or more spatial dimensions,
at this point, already applied in equations GRMHD. Finally, the
Nessyahu-Tadmor method was possible to obtain stable numerical
solutions - without spurious oscillations or excessive dissipation -
from the magnetized accretion disk process in rotation with respect
to a central black hole (BH) Schwarzschild and immersed in a
magnetosphere, for the ejection of matter in the form of jet over a
distance of fourteen times the radius of the BH, a record in terms
of astrophysical simulation of this kind. Also in our simulations,
we managed to get substructures jets. A great advantage obtained
was that, with the our code, we got simulate GRMHD equations in
a simple personal computer.
Abstract: In previous study, technique to estimate a self-location by using a lunar image is proposed.We consider the improvement of the conventional method in consideration of FPGA implementationin this paper. Specifically, we introduce Artificial Bee Colony algorithm for reduction of search time.In addition, we use fixed point arithmetic to enable high-speed operation on FPGA.
Abstract: This paper presents optimization of makespan for ‘n’
jobs and ‘m’ machines flexible job shop scheduling problem with
sequence dependent setup time using genetic algorithm (GA)
approach. A restart scheme has also been applied to prevent the
premature convergence. Two case studies are taken into
consideration. Results are obtained by considering crossover
probability (pc = 0.85) and mutation probability (pm = 0.15). Five
simulation runs for each case study are taken and minimum value
among them is taken as optimal makespan. Results indicate that
optimal makespan can be achieved with more than one sequence of
jobs in a production order.
Abstract: Since large part of electricity is generated by using
fossil based resources, energy is an important agenda for countries. In
this context, renewable energy sources are alternative to conventional
sources due to the depletion of fossil resources, increasing awareness
of climate change and global warming concerns. Solar, wind and
hydropower energy are the main renewable energy sources. Among
of them, since installed capacity of wind power has increased
approximately eight times between 2008 - November of 2014, wind
energy is a promising source for Turkey. Furthermore, signing of
Kyoto Protocol can be accepted as a milestone for Turkey's energy
policy. Turkish Government has announced Vision 2023 (energy
targets by 2023) in 2010-2014 Strategic Plan prepared by Ministry of
Energy and Natural Resources (MENR). Energy targets in this plan
can be summarized as follows: Share of renewable energy sources in
electricity generation is 30% of total electricity generation by 2023.
Installed capacity of wind energy will be 20 GW by 2023. Other
renewable energy sources such as solar, hydropower and geothermal
are encouraged with new incentive mechanisms. Dependence on
foreign energy is reduced for sustainability and energy security. On
the other hand, since Turkey is surrounded by three coastal areas,
wind energy potential is convenient for wind power application. As
of November of 2014, total installed capacity of wind power plants is
3.51 GW and a lot of wind power plants are under construction with
capacity 1.16 GW. Turkish government also encourages the locally
manufactured equipments. In this context, one of the projects funded
by private sector, universities and TUBİTAK names as MILRES is
an important project aimed to promote the use wind energy in
electricity generation. Within this project, wind turbine with 500 kW
power has been produced and will be installed at the beginning of the
2015. After that, by using the experience obtained from the first
phase of the project, a wind turbine with 2.5 MW power will be
manufactured in an industrial scale.
Abstract: Starting in 2020, an EU-wide CO2-limitation of
95 g/km is scheduled for the average of an OEMs passenger car fleet.
Taking that into consideration additional improvement measures of
the Diesel cycle are necessary in order to reduce fuel consumption
and emissions while boosting, or at the least, keeping performance
values at the same time.
The present article deals with the possibilities of an optimized
air/water charge air cooler, also called iCAC (indirect Charge Air
Cooler) for a Diesel passenger car amongst extreme-boundary
conditions. In this context, the precise objective was to show the
impact of improved intercooling with reference to the engine working
process (fuel consumption and NOx-emissions). Several extremeboundaries
- e.g. varying ambient temperatures or mountainous
routes - that will become very important in the near future regarding
RDE (Real Driving emissions) were subject of the investigation.
With the introduction of RDE in 2017 (EU6c measure), the
controversial NEDC (New European Driving Cycle) will belong to
the past and the OEMs will have to avoid harmful emissions in any
conceivable real life situation.
This is certainly going to lead to optimization-measurements at the
powertrain, which again is going to make the implementation of
iCACs, presently solely used for the premium class, more and more
attractive for compact class cars. The investigations showed a benefit
in FC between 1 and 3% for the iCAC in real world conditions.
Abstract: Particles exhausted from cars have adverse impacts on
human health. The study developed a three-dimensional particle
dispersion numerical model including particle coagulation to simulate
the particle concentration distribution under idling conditions in a
residential underground garage. The simulation results demonstrate
that particle disperses much faster in the vertical direction than that in
horizontal direction. The enhancement of particle dispersion in the
vertical direction due to the increase of cars with engine running is
much stronger than that in the car exhaust direction. Particle dispersion
from each pair of adjacent cars has little influence on each other in the
study. Average particle concentration after 120 seconds exhaust is
1.8-4.5 times higher than the initial total particles at ambient
environment. Particle pollution in the residential underground garage
is severe.
Abstract: Carbon fiber reinforced polymersarewidely used to strengthen steel structural elements. These structural elements are normally subjected to static, dynamic and fatigue loadings during their life-time. CFRP laminate is commonly used to strengthen these structures under the subjected loads. A number of studies have focused on the characteristics of CFRP sheets bonded to steel members under static, dynamic and fatigue loadings. However, there is a gap in understanding the bonding behavior between CFRP laminates and steel members under impact loading. This paper shows the effect of high load rates on this bond. CFRP laminate CFK 150/2000 was used to strengthen steel joints using Araldite 420 epoxy. The results show that applying a high load rate significantly affects the bond strength but has little influence on the effective bond length.
Abstract: Artificial Neural Network (ANN) can be trained using
back propagation (BP). It is the most widely used algorithm for
supervised learning with multi-layered feed-forward networks.
Efficient learning by the BP algorithm is required for many practical
applications. The BP algorithm calculates the weight changes of
artificial neural networks, and a common approach is to use a twoterm
algorithm consisting of a learning rate (LR) and a momentum
factor (MF). The major drawbacks of the two-term BP learning
algorithm are the problems of local minima and slow convergence
speeds, which limit the scope for real-time applications. Recently the
addition of an extra term, called a proportional factor (PF), to the
two-term BP algorithm was proposed. The third increases the speed
of the BP algorithm. However, the PF term also reduces the
convergence of the BP algorithm, and criteria for evaluating
convergence are required to facilitate the application of the three
terms BP algorithm. Although these two seem to be closely related,
as described later, we summarize various improvements to overcome
the drawbacks. Here we compare the different methods of
convergence of the new three-term BP algorithm.
Abstract: There exists some time lag between the consumption of
inputs and the production of outputs. This time lag effect should be
considered in calculating efficiency of decision making units (DMU).
Recently, a couple of DEA models were developed for considering
time lag effect in efficiency evaluation of research activities. However,
these models can’t discriminate efficient DMUs because of the nature
of basic DEA model in which efficiency scores are limited to ‘1’. This
problem can be resolved a super-efficiency model. However, a super
efficiency model sometimes causes infeasibility problem. This paper
suggests an output oriented super-efficiency model for efficiency
evaluation under the consideration of time lag effect. A case example
using a long term research project is given to compare the suggested
model with the MpO model.
Abstract: The purpose of this study was to reduce patient
waiting times, improve system throughput and improve resources
utilization in radiology department. A discrete event simulation
model was developed using Arena simulation software to investigate
different alternatives to improve the overall system delivery based on
adding resource scenarios due to the linkage between patient waiting
times and resource availability. The study revealed that there is no
addition investment need to procure additional scanner but hospital
management deploy managerial tactics to enhance machine
utilization and reduce the long waiting time in the department.
Abstract: In this paper, effect of marginal quality groundwater
on yield of cotton crop and soil salinity was studied. In this
connection, three irrigation treatments each with four replications
were applied. These treatments were i) use of canal water (T1), ii) use
of marginal quality groundwater from tubewell (T2), and iii)
conjunctive use by mixing with the ratio of 1:1 of canal water and
marginal quality tubewell water (T3).
Water was applied to the crop cultivated in Kharif season 2011; its
quantity has been measured using cut-throat flume. Total 11 watering
each of 50 mm depth have been applied from 20th April to 20th July,
2011. Further, irrigations were stopped due to monsoon rainfall up to
crop harvesting.
Maximum crop yield (seed cotton) was observed under T1 which
was 1,517 kg/ha followed by T3 (mixed canal and tubewell water)
having 1009 kg/ha and T2 i.e. marginal quality groundwater having
709 kg/ha. This concludes that crop yield in T2 and T3 in comparison
to T1was reduced by about 53 and 30% respectively.
It has been observed that yield of cotton crop is below potential
limit for three treatments due to unexpected rainfall at the time of full
flowering season; thus the yield was adversely affected.
However, salt deposition in soil profiles was not observed that is
due to leaching effect of heavy rainfall occurred during monsoon
season.
Abstract: In this study which has been conducted in Akçasu
Forest Range District of Devrek Forest Directorate; 3 methods (weed
control with labourer power, cover removal with Hitachi F20
Excavator, and weed control with agricultural equipment mounted on
a Ferguson 240S agriculture tractor) were utilized in weed control
efforts in regeneration of degraded oriental beech forests have been
compared. In this respect, 3 methods have been compared by
determining certain work hours and standard durations of unit areas
(1 hectare). For this purpose, evaluating the tasks made with human
and machine force from the aspects of duration, productivity and
costs, it has been aimed to determine the most productive method in
accordance with the actual ecological conditions of research field.
Within the scope of the study, the time studies have been conducted
for 3 methods used in weed control efforts. While carrying out those
studies, the performed implementations have been evaluated by
dividing them into business stages. Also, the actual data have been
used while calculating the cost accounts. In those calculations, the
latest formulas and equations which are also used in developed
countries have been utilized. The variance of analysis (ANOVA) was
used in order to determine whether there is any statistically
significant difference among obtained results, and the Duncan test
was used for grouping if there is significant difference. According to
the measurements and findings carried out within the scope of this
study, it has been found during living cover removal efforts in
regeneration efforts in demolished oriental beech forests that the
removal of weed layer in 1 hectare of field has taken 920 hours with
labourer force, 15.1 hours with excavator and 60 hours with an
equipment mounted on a tractor. On the other hand, it has been
determined that the cost of removal of living cover in unit area (1
hectare) was 3220.00 TL for labourer power, 1250 TL for excavator
and 1825 TL for equipment mounted on a tractor.
According to the obtained results, it has been found that the
utilization of excavator in weed control effort in regeneration of
degraded oriental beech regions under actual ecological conditions of
research field has been found to be more productive from both of
aspects of duration and costs. These determinations carried out
should be repeated in weed control efforts in degraded forest fields
with different ecological conditions, it is compulsory for finding the
most efficient weed control method. These findings will light the way
of technical staff of forestry directorate in determination of the most
effective and economic weed control method. Thus, the more actual
data will be used while preparing the weed control budgets, and there
will be significant contributions to national economy. Also the results of this and similar studies are very important for developing the policies for our forestry in short and long term.
Abstract: Many wireless sensor network applications require
K-coverage of the monitored area. In this paper, we propose a
scalable harmony search based algorithm in terms of execution
time, K-Coverage Enhancement Algorithm (KCEA), it attempts to
enhance initial coverage, and achieve the required K-coverage degree
for a specific application efficiently. Simulation results show that
the proposed algorithm achieves coverage improvement of 5.34%
compared to K-Coverage Rate Deployment (K-CRD), which achieves
1.31% when deploying one additional sensor. Moreover, the proposed
algorithm is more time efficient.
Abstract: This paper provides a comparative study on the
performances of standard PID and adaptive PID controllers tested on
travel angle of a 3-Degree-of-Freedom (3-DOF) Quanser bench-top
helicopter. Quanser, a well-known manufacturer of educational
bench-top helicopter has developed Proportional Integration
Derivative (PID) controller with Linear Quadratic Regulator (LQR)
for all travel, pitch and yaw angle of the bench-top helicopter. The
performance of the PID controller is relatively good; however, its
performance could also be improved if the controller is combined
with adaptive element. The objective of this research is to design
adaptive PID controller and then compare the performances of the
adaptive PID with the standard PID. The controller design and test is
focused on travel angle control only. Adaptive method used in this
project is self-tuning controller, which controller’s parameters are
updated online. Two adaptive algorithms those are pole-placement
and deadbeat have been chosen as the method to achieve optimal
controller’s parameters. Performance comparisons have shown that
the adaptive (deadbeat) PID controller has produced more desirable
performance compared to standard PID and adaptive (poleplacement).
The adaptive (deadbeat) PID controller attained very fast
settling time (5 seconds) and very small percentage of overshoot (5%
to 7.5%) for 10° to 30° step change of travel angle.