Abstract: In the present work steady inviscid hypersonic flows
are calculated by approximate Method. Maslens' inverse method is the chosen approximate method. For the inverse problem, parabolic
shock shape is chosen for the two-dimensional flow, and the body shape and flow field are calculated using Maslen's method. For the axisymmetric inverse problem paraboloidal shock is chosen and the
surface distribution of pressure is obtained.
Abstract: This paper proposes an improvement method of classification
efficiency in a classification model. The model is used
in a risk search system and extracts specific labels from articles
posted at bulletin board sites. The system can analyze the important
discussions composed of the articles. The improvement method
introduces ensemble learning methods that use multiple classification
models. Also, it introduces expressions related to the specific labels
into generation of word vectors. The paper applies the improvement
method to articles collected from three bulletin board sites selected
by users and verifies the effectiveness of the improvement method.
Abstract: Fractional delay FIR filters design method based on
the differential evolution algorithm is presented. Differential evolution
is an evolutionary algorithm for solving a global optimization problems in the continuous search space. In the proposed approach,
an evolutionary algorithm is used to determine the coefficients of
a fractional delay FIR filter based on the Farrow structure. Basic
differential evolution is enhanced with a restricted mating technique,
which improves the algorithm performance in terms of convergence
speed and obtained solution. Evolutionary optimization is carried out by minimizing an objective function which is based on the amplitude
response and phase delay errors. Experimental results show that the proposed algorithm leads to a reduction in the amplitude response and phase delay errors relative to those achieved with the Least-Squares
method.
Abstract: Artifact free photoplethysmographic (PPG) signals are
necessary for non-invasive estimation of oxygen saturation (SpO2) in
arterial blood. Movement of a patient corrupts the PPGs with motion
artifacts, resulting in large errors in the computation of Sp02. This
paper presents a study on using Kalman Filter in an innovative way
by modeling both the Artillery Blood Pressure (ABP) and the
unwanted signal, additive motion artifact, to reduce motion artifacts
from corrupted PPG signals. Simulation results show acceptable
performance regarding LMS and variable step LMS, thus
establishing the efficacy of the proposed method.
Abstract: Carbon nanotubes (CNTs) with their high mechanical,
electrical, thermal and chemical properties are regarded as promising
materials for many different potential applications. Having unique
properties they can be used in a wide range of fields such as
electronic devices, electrodes, drug delivery systems, hydrogen
storage, textile etc. Catalytic chemical vapor deposition (CCVD) is a
common method for CNT production especially for mass production.
Catalysts impregnated on a suitable substrate are important for
production with chemical vapor deposition (CVD) method. Iron
catalyst and MgO substrate is one of most common catalyst-substrate
combination used for CNT. In this study, CNTs were produced by
CCVD of acetylene (C2H2) on magnesium oxide (MgO) powder
substrate impregnated by iron nitrate (Fe(NO3)3•9H2O) solution. The
CNT synthesis conditions were as follows: at synthesis temperatures
of 500 and 800°C multiwall and single wall CNTs were produced
respectively. Iron (Fe) catalysts were prepared by with Fe:MgO ratio
of 1:100, 5:100 and 10:100. The duration of syntheses were 30 and
60 minutes for all temperatures and catalyst percentages. The
synthesized materials were characterized by thermal gravimetric
analysis (TGA), transmission electron microscopy (TEM) and Raman
spectroscopy.
Abstract: Online trading is an alternative to conventional shopping method. People trade goods which are new or pre-owned before. However, there are times when a user is not able to search the items wanted online. This is because the items may not be posted as yet, thus ending the search. Conventional search mechanism only works by searching and matching search criteria (requirement) with data available in a particular database. This research aims to match current search requirements with future postings. This would involve the time factor in the conventional search method. A Car Matching Alert System (CMAS) prototype was developed to test the matching algorithm. When a buyer-s search returns no result, the system saves the search and the buyer will be alerted if there is a match found based on future postings. The algorithm developed is useful and as it can be applied in other search context.
Abstract: The job shop scheduling problem (JSSP) is well known as one of the most difficult combinatorial optimization problems. This paper presents a hybrid genetic algorithm for the JSSP with the objective of minimizing makespan. The efficiency of the genetic algorithm is enhanced by integrating it with a local search method. The chromosome representation of the problem is based on operations. Schedules are constructed using a procedure that generates full active schedules. In each generation, a local search heuristic based on Nowicki and Smutnicki-s neighborhood is applied to improve the solutions. The approach is tested on a set of standard instances taken from the literature and compared with other approaches. The computation results validate the effectiveness of the proposed algorithm.
Abstract: The Wavelet-Galerkin finite element method for
solving the one-dimensional heat equation is presented in this work.
Two types of basis functions which are the Lagrange and multi-level
wavelet bases are employed to derive the full form of matrix system.
We consider both linear and quadratic bases in the Galerkin method.
Time derivative is approximated by polynomial time basis that
provides easily extend the order of approximation in time space. Our
numerical results show that the rate of convergences for the linear
Lagrange and the linear wavelet bases are the same and in order 2
while the rate of convergences for the quadratic Lagrange and the
quadratic wavelet bases are approximately in order 4. It also reveals
that the wavelet basis provides an easy treatment to improve
numerical resolutions that can be done by increasing just its desired
levels in the multilevel construction process.
Abstract: The paper deals with quality labels used in the food products market, especially with labels of quality, labels of origin, and labels of organic farming. The aim of the paper is to identify perception of these labels by consumers in the Czech Republic. The first part refers to the definition and specification of food quality labels that are relevant in the Czech Republic. The second part includes the discussion of marketing research results. Data were collected with personal questioning method. Empirical findings on 150 respondents are related to consumer awareness and perception of national and European food quality labels used in the Czech Republic, attitudes to purchases of labelled products, and interest in information regarding the labels. Statistical methods, in the concrete Pearson´s chi-square test of independence, coefficient of contingency, and coefficient of association are used to determinate if significant differences do exist among selected demographic categories of Czech consumers.
Abstract: In this study, the Taguchi method was used to optimize the effect of HALO structure or halo implant variations on threshold voltage (VTH) and leakage current (ILeak) in 45nm p-type Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) device. Besides halo implant dose, the other process parameters which used were Source/Drain (S/D) implant dose, oxide growth temperature and silicide anneal temperature. This work was done using TCAD simulator, consisting of a process simulator, ATHENA and device simulator, ATLAS. These two simulators were combined with Taguchi method to aid in design and optimize the process parameters. In this research, the most effective process parameters with respect to VTH and ILeak are halo implant dose (40%) and S/D implant dose (52%) respectively. Whereas the second ranking factor affecting VTH and ILeak are oxide growth temperature (32%) and halo implant dose (34%) respectively. The results show that after optimizations approaches is -0.157V at ILeak=0.195mA/μm.
Abstract: This paper tries to represent a new method for
computing the reliability of a system which is arranged in series or
parallel model. In this method we estimate life distribution function
of whole structure using the asymptotic Extreme Value (EV)
distribution of Type I, or Gumbel theory. We use EV distribution in
minimal mode, for estimate the life distribution function of series
structure and maximal mode for parallel system. All parameters also
are estimated by Moments method. Reliability function and failure
(hazard) rate and p-th percentile point of each function are
determined. Other important indexes such as Mean Time to Failure
(MTTF), Mean Time to repair (MTTR), for non-repairable and
renewal systems in both of series and parallel structure will be
computed.
Abstract: In the present paper, active control system is used in
different heights of the building and the most effective part was
studied where the active control system is applied. The mathematical
model of the building is established in MATLAB and in order to
active control the system FLC method was used. Three different
locations of the building are chosen to apply active control system,
namely at the lowest story, the middle height of the building, and at
the highest point of the building with TMD system. The equation of
motion was written for high rise building and it was solved by statespace
method. Also passive control was used with Tuned Mass
Damper (TMD) at the top floor of the building to show the robustness
of FLC method when compared with passive control system.
Abstract: A new design of a planar passive T-micromixer with fin-shaped baffles in the mixing channel is presented. The mixing efficiency and the level of pressure loss in the channel have been investigated by numerical simulations in the range of Reynolds number (Re) 1 to 50. A Mixing index (Mi) has been defined to quantify the mixing efficiency, which results over 85% at both ends of the Re range, what demonstrates the micromixer can enhance mixing using the mechanisms of diffusion (lower Re) and convection (higher Re). Three geometric dimensions: radius of baffle, baffles pitch and height of the channel define the design parameters, and the mixing index and pressure loss are the performance parameters used to optimize the micromixer geometry with a multi-criteria optimization method. The Pareto front of designs with the optimum trade-offs, maximum mixing index with minimum pressure loss, is obtained. Experiments for qualitative and quantitative validation have been implemented.
Abstract: The struggle between modern and postmodern
understanding is also displayed in terms of the superiorities of
quantitative and qualitative methods to each other which are
evaluated within the scope of these understandings. By way of
assuming that the quantitative researches (modern) are able to
account for structure while the qualitative researches (postmodern)
explain the process, these methods are turned into a means for
worldviews specific to a period. In fact, process is not a functioning
independent of structure. In addition to this issue, the ability of
quantitative methods to provide scientific knowledge is also
controversial so long as they exclude the dialectical method. For this
reason, the critiques charged against modernism in terms of
quantitative methods are, in a sense, legitimate. Nevertheless, the
main issue is in which parameters postmodernist critique tries to
legitimize its critiques and whether these parameters represent a point
of view enabling democratic solutions.
In this respect, the scientific knowledge covered in Turkish media
as a means through which ordinary people have access to scientific
knowledge will be evaluated by means of content analysis within a
new objectivity conception.
Abstract: The problem of robust stability and robust stabilization for a class of discrete-time uncertain systems with time delay is investigated. Based on Tchebychev inequality, by constructing a new augmented Lyapunov function, some improved sufficient conditions ensuring exponential stability and stabilization are established. These conditions are expressed in the forms of linear matrix inequalities (LMIs), whose feasibility can be easily checked by using Matlab LMI Toolbox. Compared with some previous results derived in the literature, the new obtained criteria have less conservatism. Two numerical examples are provided to demonstrate the improvement and effectiveness of the proposed method.
Abstract: This paper explores the effectiveness of machine
learning techniques in detecting firms that issue fraudulent financial
statements (FFS) and deals with the identification of factors
associated to FFS. To this end, a number of experiments have been
conducted using representative learning algorithms, which were
trained using a data set of 164 fraud and non-fraud Greek firms in the
recent period 2001-2002. The decision of which particular method to
choose is a complicated problem. A good alternative to choosing
only one method is to create a hybrid forecasting system
incorporating a number of possible solution methods as components
(an ensemble of classifiers). For this purpose, we have implemented
a hybrid decision support system that combines the representative
algorithms using a stacking variant methodology and achieves better
performance than any examined simple and ensemble method. To
sum up, this study indicates that the investigation of financial
information can be used in the identification of FFS and underline the
importance of financial ratios.
Abstract: This work considered the thermodynamic feasibility
of scrubbing volatile organic compounds into biodiesel in view of
designing a gas treatment process with this absorbent. A detailed
vapour – liquid equilibrium investigation was performed using the
original UNIFAC group contribution method. The four biodiesels
studied in this work are methyl oleate, methyl palmitate, methyl
linolenate and ethyl stearate. The original UNIFAC procedure was
used to estimate the infinite dilution activity coefficients of 13
selected volatile organic compounds in the biodiesels. The
calculations were done at the VOC mole fraction of 9.213x10-8. Ethyl
stearate gave the most favourable phase equilibrium. A close
agreement was found between the infinite dilution activity coefficient
of toluene found in this work and those reported in literature.
Thermodynamic models can efficiently be used to calculate vast
amount of phase equilibrium behaviour using limited number of
experimental data.
Abstract: In this paper, we have proposed two novel plasmonic demultiplexing structures based on metal-insulator-metal surfaces which, beside their compact size, have a very good transmission spectrum. The impact of the key internal parameters on the transmission spectrum is numerically analyzed by using the twodimensional (2D) finite difference time domain (FDTD) method. The proposed structures could be used to develop ultra-compact photonic wavelength demultiplexing devices for large-scale photonic integration.
Abstract: In this paper, the details of an experimental method to measure the clamping force value at bolted connections due to application of wrenching torque to tighten the nut have been presented. A simplified bolted joint including a holed plate with a single bolt was considered to carry out the experiments. This method was designed based on Hooke-s law by measuring compressive axial strain of a steel bush placed between the nut and the plate. In the experimental procedure, the values of clamping force were calculated for seven different levels of applied torque, and this process was repeated three times for each level of the torque. Moreover, the effect of lubrication of threads on the clamping value was studied using the same method. In both conditions (dry and lubricated threads), relation between the torque and the clamping force have been displayed in graphs.
Abstract: Solid fuel transient burning behavior under oxidizer
gas flow is numerically investigated. It is done using analysis of the
regression rate responses to the imposed sudden and oscillatory
variation at inflow properties. The conjugate problem is considered
by simultaneous solution of flow and solid phase governing
equations to compute the fuel regression rate. The advection
upstream splitting method is used as flow computational scheme in
finite volume method. The ignition phase is completely simulated to
obtain the exact initial condition for response analysis. The results
show that the transient burning effects which lead to the combustion
instabilities and intermittent extinctions could be observed in solid
fuels as the solid propellants.