Abstract: This paper deals with heterogeneous autoregressive
models of realized volatility (HAR-RV models) on high-frequency
data of stock indices in the USA. Its aim is to capture the behavior of
three groups of market participants trading on a daily, weekly and
monthly basis and assess their role in predicting the daily realized
volatility. The benefits of this work lies mainly in the application of
heterogeneous autoregressive models of realized volatility on stock
indices in the USA with a special aim to analyze an impact of the
global financial crisis on applied models forecasting performance.
We use three data sets, the first one from the period before the global
financial crisis occurred in the years 2006-2007, the second one from
the period when the global financial crisis fully hit the U.S. financial
market in 2008-2009 years, and the last period was defined over
2010-2011 years. The model output indicates that estimated realized
volatility in the market is very much determined by daily traders and
in some cases excludes the impact of those market participants who
trade on monthly basis.
Abstract: A simple approach is demonstrated for growing large
scale, nearly vertically aligned ZnO nanowire arrays by thermal
oxidation method. To reveal effect of temperature on growth and
physical properties of the ZnO nanowires, gold coated zinc substrates
were annealed at 300 °C and 400 °C for 4 hours duration in air. Xray
diffraction patterns of annealed samples indicated a set of well
defined diffraction peaks, indexed to the wurtzite hexagonal phase of
ZnO. The scanning electron microscopy studies show formation of
ZnO nanowires having length of several microns and average of
diameter less than 500 nm. It is found that the areal density of wires
is relatively higher, when the annealing is carried out at higher
temperature i.e. at 400°C. From the field emission studies, the values
of the turn-on and threshold field, required to draw emission current
density of 10 μA/cm2 and 100 μA/cm2 are observed to be 1.2 V/μm
and 1.7 V/μm for the samples annealed at 300 °C and 2.9 V/μm and
3.7 V/μm for that annealed at 400 °C, respectively. The field
emission current stability, investigated over duration of more than 2
hours at the preset value of 1 μA, is found to be fairly good in both
cases. The simplicity of the synthesis route coupled with the
promising field emission properties offer unprecedented advantage
for the use of ZnO field emitters for high current density
applications.
Abstract: This paper considers inference under progressive type II censoring with a compound Rayleigh failure time distribution. The maximum likelihood (ML), and Bayes methods are used for estimating the unknown parameters as well as some lifetime parameters, namely reliability and hazard functions. We obtained Bayes estimators using the conjugate priors for two shape and scale parameters. When the two parameters are unknown, the closed-form expressions of the Bayes estimators cannot be obtained. We use Lindley.s approximation to compute the Bayes estimates. Another Bayes estimator has been obtained based on continuous-discrete joint prior for the unknown parameters. An example with the real data is discussed to illustrate the proposed method. Finally, we made comparisons between these estimators and the maximum likelihood estimators using a Monte Carlo simulation study.
Abstract: Medical applications are among the most impactful
areas of microrobotics. The ultimate goal of medical microrobots is
to reach currently inaccessible areas of the human body and carry out
a host of complex operations such as minimally invasive surgery
(MIS), highly localized drug delivery, and screening for diseases at
their very early stages. Miniature, safe and efficient propulsion
systems hold the key to maturing this technology but they pose
significant challenges. A new type of propulsion developed recently,
uses multi-flagella architecture inspired by the motility mechanism of
prokaryotic microorganisms. There is a lack of efficient methods for
designing this type of propulsion system. The goal of this paper is to
overcome the lack and this way, a numerical strategy is proposed to
design multi-flagella propulsion systems. The strategy is based on the
implementation of the regularized stokeslet and rotlet theory, RFT
theory and new approach of “local corrected velocity". The effects of
shape parameters and angular velocities of each flagellum on overall
flow field and on the robot net forces and moments are considered.
Then a multi-layer perceptron artificial neural network is designed
and employed to adjust the angular velocities of the motors for
propulsion control. The proposed method applied successfully on a
sample configuration and useful demonstrative results is obtained.
Abstract: Computer based geostatistical methods can offer effective data analysis possibilities for agricultural areas by using
vectorial data and their objective informations. These methods will help to detect the spatial changes on different locations of the large
agricultural lands, which will lead to effective fertilization for optimal yield with reduced environmental pollution. In this study, topsoil (0-20 cm) and subsoil (20-40 cm) samples were taken from a
sugar beet field by 20 x 20 m grids. Plant samples were also collected
from the same plots. Some physical and chemical analyses for these
samples were made by routine methods. According to derived variation coefficients, topsoil organic matter (OM) distribution was more than subsoil OM distribution. The highest C.V. value of
17.79% was found for topsoil OM. The data were analyzed
comparatively according to kriging methods which are also used
widely in geostatistic. Several interpolation methods (Ordinary,Simple and Universal) and semivariogram models (Spherical,
Exponential and Gaussian) were tested in order to choose the suitable
methods. Average standard deviations of values estimated by simple
kriging interpolation method were less than average standard
deviations (topsoil OM ± 0.48, N ± 0.37, subsoil OM ± 0.18) of measured values. The most suitable interpolation method was simple
kriging method and exponantial semivariogram model for topsoil,
whereas the best optimal interpolation method was simple kriging
method and spherical semivariogram model for subsoil. The results
also showed that these computer based geostatistical methods should
be tested and calibrated for different experimental conditions and semivariogram models.
Abstract: The role of corporate governance is to reduce the
divergence of interests between shareholders and managers. The role
of corporate governance is more useful when managers have an
incentive to deviate from shareholders- interests. One example of
management-s deviation from shareholders- interests is the
management of earnings through the use of accounting accruals. This
paper examines the association between corporate governance
internal mechanisms ownership concentration, board independence,
the existence of CEO-Chairman duality and earnings management.
Firm size and leverage are control variables. The population used in
this study comprises firms listed on the Tehran Stock Exchange
(TSE) between 2004 and 2008, the sample comprises 196 firms.
Panel Data method is employed as technique to estimate the model.
We find that there is negative significant association between
ownership concentration and board independence manage earnings
with earnings management, there is negative significant association
between the existence of CEO-Chairman duality and earnings
management. This study also found a positive significant association
between control variable (firm size and leverage) and earnings
management.
Abstract: Recognition of characters greatly depends upon the features used. Several features of the handwritten Arabic characters are selected and discussed. An off-line recognition system based on the selected features was built. The system was trained and tested with realistic samples of handwritten Arabic characters. Evaluation of the importance and accuracy of the selected features is made. The recognition based on the selected features give average accuracies of 88% and 70% for the numbers and letters, respectively. Further improvements are achieved by using feature weights based on insights gained from the accuracies of individual features.
Abstract: novel and simple method is introduced for rapid and
highly efficient water treatment by reverse osmosis (RO) method using
multi-walled carbon nanotubes (MWCNTs) / polyacrylonitrile (PAN)
polymer as a flexible, highly efficient, reusable and semi-permeable
mixed matrix membrane (MMM). For this purpose, MWCNTs were
directly synthesized and on-line purified by chemical vapor deposition
(CVD) process, followed by directing the MWCNT bundles towards an
ultrasonic bath, in which PAN polymer was simultaneously suspended
inside a solid porous silica support in water at temperature to ~70 οC.
Fabrication process of MMM was finally completed by hot isostatic
pressing (HIP) process. In accordance with the analytical figures of
merit, the efficiency of fabricated MMM was ~97%. The rate of water
treatment process was also evaluated to 6.35 L min-1. The results reveal
that, the CNT-based MMM is suitable for rapid treatment of different
forms of industrial, sea, drinking and well water samples.
Abstract: This paper presents a novel method for prediction of
the mechanical behavior of proximal femur using the general
framework of the quantitative computed tomography (QCT)-based
finite element Analysis (FEA). A systematic imaging and modeling
procedure was developed for reliable correspondence between the
QCT-based FEA and the in-vitro mechanical testing. A speciallydesigned
holding frame was used to define and maintain a unique
geometrical reference system during the analysis and testing. The
QCT images were directly converted into voxel-based 3D finite
element models for linear and nonlinear analyses. The equivalent
plastic strain and the strain energy density measures were used to
identify the critical elements and predict the failure patterns. The
samples were destructively tested using a specially-designed gripping
fixture (with five degrees of freedom) mounted within a universal
mechanical testing machine. Very good agreements were found
between the experimental and the predicted failure patterns and the
associated load levels.
Abstract: In this article, we propose a methodology for the
characterization of the suspended matter along Algiers-s bay. An
approach by multi layers perceptron (MLP) with training by back
propagation of the gradient optimized by the algorithm of Levenberg
Marquardt (LM) is used. The accent was put on the choice of the
components of the base of training where a comparative study made
for four methods: Random and three alternatives of classification by
K-Means. The samples are taken from suspended matter image,
obtained by analytical model based on polynomial regression by
taking account of in situ measurements. The mask which selects the
zone of interest (water in our case) was carried out by using a multi
spectral classification by ISODATA algorithm. To improve the
result of classification, a cleaning of this mask was carried out using
the tools of mathematical morphology. The results of this study
presented in the forms of curves, tables and of images show the
founded good of our methodology.
Abstract: Horizontal wells are proven to be better producers
because they can be extended for a long distance in the pay zone.
Engineers have the technical means to forecast the well productivity
for a given horizontal length. However, experiences have shown that
the actual production rate is often significantly less than that of
forecasted. It is a difficult task, if not impossible to identify the real
reason why a horizontal well is not producing what was forecasted.
Often the source of problem lies in the drilling of horizontal section
such as permeability reduction in the pay zone due to mud invasion
or snaky well patterns created during drilling. Although drillers aim
to drill a constant inclination hole in the pay zone, the more frequent
outcome is a sinusoidal wellbore trajectory. The two factors, which
play an important role in wellbore tortuosity, are the inclination and
side force at bit. A constant inclination horizontal well can only be
drilled if the bit face is maintained perpendicular to longitudinal axis
of bottom hole assembly (BHA) while keeping the side force nil at
the bit. This approach assumes that there exists no formation force at
bit. Hence, an appropriate BHA can be designed if bit side force and
bit tilt are determined accurately. The Artificial Neural Network
(ANN) is superior to existing analytical techniques. In this study, the
neural networks have been employed as a general approximation tool
for estimation of the bit side forces. A number of samples are
analyzed with ANN for parameters of bit side force and the results
are compared with exact analysis. Back Propagation Neural network
(BPN) is used to approximation of bit side forces. Resultant low
relative error value of the test indicates the usability of the BPN in
this area.
Abstract: This paper proposes a dual tree complex wavelet transform (DT-CWT) based directional interpolation scheme for noisy images. The problems of denoising and interpolation are modelled as to estimate the noiseless and missing samples under the same framework of optimal estimation. Initially, DT-CWT is used to decompose an input low-resolution noisy image into low and high frequency subbands. The high-frequency subband images are interpolated by linear minimum mean square estimation (LMMSE) based interpolation, which preserves the edges of the interpolated images. For each noisy LR image sample, we compute multiple estimates of it along different directions and then fuse those directional estimates for a more accurate denoised LR image. The estimation parameters calculated in the denoising processing can be readily used to interpolate the missing samples. The inverse DT-CWT is applied on the denoised input and interpolated high frequency subband images to obtain the high resolution image. Compared with the conventional schemes that perform denoising and interpolation in tandem, the proposed DT-CWT based noisy image interpolation method can reduce many noise-caused interpolation artifacts and preserve well the image edge structures. The visual and quantitative results show that the proposed technique outperforms many of the existing denoising and interpolation methods.
Abstract: The two agro-ecological zones became the focus of
the study because of violent nature of the incessant conflict in the
zones. The available register of farmers association was the sampling
frame work where ten percent (61) farmers per state were randomly
sampled. Data were collected and analysed using z-test. The research
findings revealed tree crops and grains production enterprises ranked
higher in Osun (rain fed zones) and Taraba states (savannah zones)
respectively. Osun state entrepreneur felt the effect of the conflict on
their enterprises more than Tarba state. The reasons adduced for
severity of the conflict on enterprises are majority (77.0%) migrated
and (75.5%) of them were not allowed to enter their farms during and
when conflict deescalated unlike situation in Taraba state. The
different in enterprises production level between the two agroecological
zone was statistically significant at p
Abstract: Feature-based registration is an effective technique for clinical use, because it can greatly reduce computational costs. However, this technique, which estimates the transformation by using feature points extracted from two images, may cause misalignments. To handle with this limitation, we propose to extract the salient edges and extracted control points (CP) of medical images by using efficiency of multiresolution representation of data nonsubsampled contourlet transform (NSCT) that finds the best feature points. The MR images were first decomposed using the NSCT, and then Edge and CP were extracted from bandpass directional subband of NSCT coefficients and some proposed rules. After edge and CP extraction, mutual information was adopted for the registration of feature points and translation parameters are calculated by using particle swarm optimization (PSO). The experimental results showed that the proposed method produces totally accurate performance for registration medical CT-MR images.
Abstract: The direct sewage sludge application is a relative
cheap method for their liquidation. In the past heavy metal contents
increase in soils treated with sewage sludge was observed. In 2003
there was acceptance on act n.188/2003 about sewage sludge
application on soils. The basic philosophy of act is a safety of the
environmental proof of sludge application on soils. The samples of
soils from wastewater treatment plant (WTP) Poprad (35) and WTP
Michalovce (33 samples) were analyzed which were chosen for
sludge application on soils. According to the results only 14 areas for
Poprad and 25 areas for Michalovce are suitable for sludge
application according to act No. 188/2003. The application dose of
sludge was calculated 50 t.ha-1 or 75 t. ha-1 once in 5 years to ensure
that heavy metal contents in treated soils will be kept.
Abstract: The present research focus on the processing of mullite-based ceramics from oil refinery industrial wastes and byproducts of agricultural industry and on the investigating of silane modified surface of ceramics. Two waste products were used as initial material – waste aluminum oxide and waste rice husk. The burning - out additives used were waste rise husk. It is known that the oxide ceramics surface is hydrophilic due to the presence of – OH groups in it. The nature of ceramic surface regarding permeation of water and hydrocarbons can be changed by further treatment with silanes. The samples were studied mainly by X-ray analysis, FT-IR absorbance measurements and microscopic analysis. The X-ray analyses showed the phase composition depends on the firing temperature and on the purity of the starting alumina. Two kind of silanes were used for the transformation of surface from hydrophilic to hydrophobic – trimethoxymethylsilane (TMMS) and trimethylclorsilane (TMCS).
Abstract: Shirvan is located in plain in Northern Khorasan province north east of Iran and has semiarid to temperate climate. To investigate the annual changes in some qualitative parameters such as electrical conductivity, total dissolved solids and chloride concentrations which have increased during ten continuous years. Fourteen groundwater sources including deep as well as semi-deep wells were sampled and were analyzed using standard methods. The trends of obtained data were analyzed during these years and the effects of different factors on the changes in electrical conductivity, concentration of chloride and total dissolved solids were clarified. The results showed that the amounts of some qualitative parameters have been increased during 10 years time which has led to decrease in water quality. The results also showed that increased in urban populations as well as extensive industrialization in the studied area are the most important reasons to influence underground water quality. Furthermore decrease in water quantity is also evident due to more water utilization and occurrence of recent droughts in the region during recent years.
Abstract: To understand the seismic behavior of the offshore
structures, the dynamic interaction of the water-structure-soil should
be assessed. In this regard the role of the water dynamic properties in
magnifying or reducing of the effects of earthquake induced motions
on offshore structures haven't been investigated in precise manner in
available literature. In this paper the sea water level fluctuations
effects on the seismic behavior of a sample of offshore structures has
been investigated by emphasizing on the water-structure interaction
phenomenon. For this purpose a two dimensional finite element
model of offshore structures as well as surrounded water has been
developed using ANSYS software. The effect of soil interaction with
embedded pile foundation has been imposed by using a series of
nonlinear springs in horizontal and vertical directions in soil-piles
contact points. In the model, the earthquake induced motions have
been applied on springs and consequently the motions propagated
upward to the structure and surrounded water. As a result of
numerical study, the horizontal deformations of the offshore deck as
well as internal force and buckling coefficient in structural elements
have been recorded and controlled with and without water presence.
In part of study a parametric study has been accomplished on sea
water level fluctuations and effect of this parameter has been studied
on the aforementioned numerical results.
Abstract: This paper presents an online method that learns the
corresponding points of an object from un-annotated grayscale images
containing instances of the object. In the first image being
processed, an ensemble of node points is automatically selected
which is matched in the subsequent images. A Bayesian posterior
distribution for the locations of the nodes in the images is formed.
The likelihood is formed from Gabor responses and the prior assumes
the mean shape of the node ensemble to be similar in a translation
and scale free space. An association model is applied for separating
the object nodes and background nodes. The posterior distribution is
sampled with Sequential Monte Carlo method. The matched object
nodes are inferred to be the corresponding points of the object
instances. The results show that our system matches the object nodes
as accurately as other methods that train the model with annotated
training images.
Abstract: A multimedia presentation system refers to the integration of a multimedia database with a presentation manager which has the functionality of content selection, organization and playout of multimedia presentations. It requires high performance of involved system components. Starting from multimedia information capture until the presentation delivery, high performance tools are required for accessing, manipulating, storing and retrieving these segments, for transferring and delivering them in a presentation terminal according to a playout order. The organization of presentations is a complex task in that the display order of presentation contents (in time and space) must be specified. A multimedia presentation contains audio, video, images and text media types. The critical decisions for presentation construction include what the contents are, how the contents are organized, and once the decision is made on the organization of the contents of the presentation, it must be conveyed to the end user in the correct organizational order and in a timely fashion. This paper introduces a framework for specification of multimedia presentations and describes the design of sample presentations using this framework from a multimedia database.