Abstract: A low-complexity, high-accurate frequency offset
estimation for multi-band orthogonal frequency division multiplexing (MB-OFDM) based ultra-wide band systems is presented regarding different carrier frequency offsets, different channel frequency
responses, different preamble patterns in different bands. Utilizing a
half-cycle Constant Amplitude Zero Auto Correlation (CAZAC) sequence as the preamble sequence, the estimator with a semi-cross
contrast scheme between two successive OFDM symbols is proposed. The CRLB and complexity of the proposed algorithm are derived.
Compared to the reference estimators, the proposed method achieves
significantly less complexity (about 50%) for all preamble patterns of the MB-OFDM systems. The CRLBs turn out to be of well performance.
Abstract: Text similarity measurement is a fundamental issue in
many textual applications such as document clustering, classification,
summarization and question answering. However, prevailing approaches
based on Vector Space Model (VSM) more or less suffer
from the limitation of Bag of Words (BOW), which ignores the semantic
relationship among words. Enriching document representation
with background knowledge from Wikipedia is proven to be an effective
way to solve this problem, but most existing methods still
cannot avoid similar flaws of BOW in a new vector space. In this
paper, we propose a novel text similarity measurement which goes
beyond VSM and can find semantic affinity between documents.
Specifically, it is a unified graph model that exploits Wikipedia as
background knowledge and synthesizes both document representation
and similarity computation. The experimental results on two different
datasets show that our approach significantly improves VSM-based
methods in both text clustering and classification.
Abstract: Cryo-electron microscopy (CEM) in combination with
single particle analysis (SPA) is a widely used technique for
elucidating structural details of macromolecular assemblies at closeto-
atomic resolutions. However, development of automated software
for SPA processing is still vital since thousands to millions of
individual particle images need to be processed. Here, we present our
workflow for automated particle picking. Our approach integrates
peak shape analysis to the classical correlation and an iterative
approach to separate macromolecules and background by
classification. This particle selection workflow furthermore provides
a robust means for SPA with little user interaction. Processing
simulated and experimental data assesses performance of the
presented tools.
Abstract: Recently, permeable breakwaters have been suggested to overcome the disadvantages of fully protection breakwaters. These protection structures have minor impacts on the coastal environment and neighboring beaches where they provide a more economical protection from waves and currents. For regular waves, a numerical model is used (FLOW-3D, VOF) to investigate the hydraulic performance of a permeable breakwater. The model of permeable breakwater consists of a pair of identical vertical slotted walls with an impermeable upper and lower part, where the draft is a decimal multiple of the total depth. The middle part is permeable with a porosity of 50%. The second barrier is located at distant of 0.5 and 1.5 of the water depth from the first one. The numerical model is validated by comparisons with previous laboratory data and semi-analytical results of the same model. A good agreement between the numerical results and both laboratory data and semi-analytical results has been shown and the results indicate the applicability of the numerical model to reproduce most of the important features of the interaction. Through the numerical investigation, the friction factor of the model is carefully discussed.
Abstract: Atherosclerosis is the condition in which an artery
wall thickens as the result of a build-up of fatty materials such as
cholesterol. It is a syndrome affecting arterial blood vessels, a
chronic inflammatory response in the walls of arteries, in large part
due to the accumulation of macrophage white blood cells and
promoted by low density (especially small particle) lipoproteins
(plasma proteins that carry cholesterol and triglycerides) without
adequate removal of fats and cholesterol from the macrophages by
functional high density lipoproteins (HDL). It is commonly referred
to as a hardening or furring of the arteries. It is caused by the
formation of multiple plaques within the arteries.
Abstract: TTV is an unenveloped circular single-stranded DNA
virus with a diameter of 30-32 nm that first was described in 1997 in
Japan. TTV was detected in various populations without proven
pathology, including blood donors and in patients with chronic HBV
and HCV hepatitis. The aim of this study was to determine the
prevalence of TTV DNA in Iranian patients with chronic hepatitis B
and C. Viral TTV-DNA was studied in 442 samples (202 with HBV,
138 with HCV and 102 controls) collected from west south of Iran.
All extracted serum DNA was amplified by TTV ORF1 gene specific
primers using the semi nested PCR technique. TTV DNA was
detected in the serum of 8.9% and 10.8% patients with chronic
hepatitis B and C, respectively. Prevalence of TTV-DNA in the serum
of 102 controls was 2.9%. Results showed significant relation of TTV
with HBV and HCV in patients by using T test examination (P
Abstract: A compact tunable 10 W picosecond source based on
Yb-doped fiber amplification of gain switch laser diode has been
demonstrated. A gain switch semiconductor laser diode was used as
the seed source, and a multi-stage single mode Yb-doped fiber
preamplifier was combined with two large mode area double-clad
Yb-doped fiber main amplifiers to construct the amplification system.
The tunable pulses with high stability and excellent beam quality
(M2
Abstract: This main purpose of the study reported here was to
investigate the extent to which the form of school
governance (particularly decision-making) had an impact upon the
effectiveness of the school with reference to parental involvement,
planning and budgeting, professional development of teachers,
school facilities and resources, and student outcomes. Particular
attention was given to decision-making within the governance
arrangements. The study was based on four case studies of high
schools in New South Wales, Australia including one government
school, one independent Christian community school, one
independent Catholic school, and one Catholic systemic school.
The focus of the research was principals, teachers, parents, and
students of four schools with varying governance structures. To
gain a greater insight into the issues, the researchers collected
information by questionnaire, semi-structured interview, and
review of school key documents. This study found that it was not
so much structure but the centrality of the school Principal and the
way that the Principal perceived his/her roles in relation to others
that impacted most on school governance.
Abstract: to simulate the phenomenon of electronic transport in semiconductors, we try to adapt a numerical method, often and most frequently it’s that of Monte Carlo. In our work, we applied this method in the case of a ternary alloy semiconductor GaInP in its cubic form; The Calculations are made using a non-parabolic effective-mass energy band model. We consider a band of conduction to three valleys (ΓLX), major of the scattering mechanisms are taken into account in this modeling, as the interactions with the acoustic phonons (elastic collisions) and optics (inelastic collisions). The polar optical phonons cause anisotropic collisions, intra-valleys, very probable in the III-V semiconductors. Other optical phonons, no polar, allow transitions inter-valleys. Initially, we present the full results obtained by the simulation of Monte Carlo in GaInP in stationary regime. We consider thereafter the effects related to the application of an electric field varying according to time, we thus study the transient phenomenon which make their appearance in ternary material
Abstract: Circular knitting machine makes the fabric with more than two knitting tools. Variation of yarn tension between different knitting tools causes different loop length of stitches duration knitting process. In this research, a new intelligent method is applied to control loop length of stitches in various tools based on ideal shape of stitches and real angle of stitches direction while different loop length of stitches causes stitches deformation and deviation those of angle. To measure deviation of stitch direction against variation of tensions, image processing technique was applied to pictures of different fabrics with constant front light. After that, the rate of deformation is translated to needed compensation of loop length cam degree to cure stitches deformation. A fuzzy control algorithm was applied to loop length modification in knitting tools. The presented method was experienced for different knitted fabrics of various structures and yarns. The results show that presented method is useable for control of loop length variation between different knitting tools based on stitch deformation for various knitted fabrics with different fabric structures, densities and yarn types.
Abstract: The issue of classifying objects into one of predefined
groups when the measured variables are mixed with different types
of variables has been part of interest among statisticians in many
years. Some methods for dealing with such situation have been
introduced that include parametric, semi-parametric and nonparametric
approaches. This paper attempts to discuss on a problem
in classifying a data when the number of measured mixed variables is
larger than the size of the sample. A propose idea that integrates a
dimensionality reduction technique via principal component analysis
and a discriminant function based on the location model is discussed.
The study aims in offering practitioners another potential tool in a
classification problem that is possible to be considered when the
observed variables are mixed and too large.
Abstract: The information on the Web increases tremendously.
A number of search engines have been developed for searching Web
information and retrieving relevant documents that satisfy the
inquirers needs. Search engines provide inquirers irrelevant
documents among search results, since the search is text-based rather
than semantic-based. Information retrieval research area has
presented a number of approaches and methodologies such as
profiling, feedback, query modification, human-computer interaction,
etc for improving search results. Moreover, information retrieval has
employed artificial intelligence techniques and strategies such as
machine learning heuristics, tuning mechanisms, user and system
vocabularies, logical theory, etc for capturing user's preferences and
using them for guiding the search based on the semantic analysis
rather than syntactic analysis. Although a valuable improvement has
been recorded on search results, the survey has shown that still
search engines users are not really satisfied with their search results.
Using ontologies for semantic-based searching is likely the key
solution. Adopting profiling approach and using ontology base
characteristics, this work proposes a strategy for finding the exact
meaning of the query terms in order to retrieve relevant information
according to user needs. The evaluation of conducted experiments
has shown the effectiveness of the suggested methodology and
conclusion is presented.
Abstract: In this paper, the Fuzzy Autocatalytic Set (FACS) is
composed into Omega Algebra by embedding the membership value
of fuzzy edge connectivity using the property of transitive affinity.
Then, the Omega Algebra of FACS is a transformation semigroup
which is a special class of semigroup is shown.
Abstract: This paper presents a novel three-phase utility
frequency to high frequency soft switching power conversion circuit
with dual mode pulse width modulation and pulse density modulation
for high power induction heating applications as melting of steel and
non ferrous metals, annealing of metals, surface hardening of steel
and cast iron work pieces and hot water producers, steamers and
super heated steamers. This high frequency power conversion circuit
can operate from three-phase systems to produce high current for
high power induction heating applications under the principles of
ZVS and it can regulate its ac output power from the rated value to a
low power level. A dual mode modulation control scheme based on
high frequency PWM in synchronization with the utility frequency
positive and negative half cycles for the proposed high frequency
conversion circuit and utility frequency pulse density modulation is
produced to extend its soft switching operating range for wide ac
output power regulation. A dual packs heat exchanger assembly is
designed to be used in consumer and industrial fluid pipeline systems
and it is proved to be suitable for the hot water, steam and super
heated steam producers. Experiment and simulation results are given
in this paper to verify the operation principles of the proposed ac
conversion circuit and to evaluate its power regulation and
conversion efficiency. Also, the paper presents a mutual coupling
model of the induction heating load instead of equivalent transformer
circuit model.
Abstract: The objective of this paper is to present a
comparative study of Homotopy Perturbation Method (HPM),
Variational Iteration Method (VIM) and Homotopy Analysis
Method (HAM) for the semi analytical solution of Kortweg-de
Vries (KdV) type equation called KdV. The study have been
highlighted the efficiency and capability of aforementioned methods
in solving these nonlinear problems which has been arisen from a
number of important physical phenomenon.
Abstract: Most HWRs currently use natural uranium fuel. Using enriched uranium fuel results in a significant improvement in fuel cycle costs and uranium utilization. On the other hand, reactivity changes of HWRs over the full range of operating conditions from cold shutdown to full power are small. This reduces the required reactivity worth of control devices and minimizes local flux distribution perturbations, minimizing potential problems due to transient local overheating of fuel. Analyzing heavy water effectiveness on neutronic parameters such as enrichment requirements, peaking factor and reactivity is important and should pay attention as primary concepts of a HWR core designing. Two nuclear nuclear reactors of CANDU-type and hexagonal-type reactor cores of 33 fuel assemblies and 19 assemblies in 1.04 P/D have been respectively simulated using MCNP-4C code. Using heavy water and light water as moderator have been compared for achieving less reactivity insertion and enrichment requirements. Two fuel matrixes of (232Th/235U)O2 and (238/235U)O2 have been compared to achieve more economical and safe design. Heavy water not only decreased enrichment needs, but it concluded in negative reactivity insertions during moderator density variations. Thorium oxide fuel assemblies of 2.3% enrichment loaded into the core of heavy water moderator resulted in 0.751 fission to absorption ratio and peaking factor of 1.7 using. Heavy water not only provides negative reactivity insertion during temperature raises which changes moderator density but concluded in 2 to 10 kg reduction of enrichment requirements, depend on geometry type.
Abstract: This article discusses the problem of estimating the
orientation of inclined ground on which a human subject stands based
on information provided by the vestibular system consisting of the
otolith and semicircular canals. It is assumed that body segments are
not necessarily aligned and thus forming an open kinematic chain.
The semicircular canals analogues to a technical gyrometer provide a
measure of the angular velocity whereas the otolith analogues to a
technical accelerometer provide a measure of the translational
acceleration. Two solutions are proposed and discussed. The first is
based on a stand-alone Kalman filter that optimally fuses the two
measurements based on their dynamic characteristics and their noise
properties. In this case, no body dynamic model is needed. In the
second solution, a central extended disturbance observer that
incorporates a body dynamic model (internal model) is employed.
The merits of both solutions are discussed and demonstrated by
experimental and simulation results.
Abstract: Homogeneous composites of alumina and zirconia
with a small amount of MgO (99%) were obtained for ZTA ceramic containing 0.05 wt% MgO in
1500 °C.
Abstract: We present a numerical study of the sensitivity of the so called time relaxation family of models of fluid motion with respect to the time relaxation parameter χ on the two dimensional cavity problem. The goal of the study is to compute and compare the sensitivity of the model using finite difference method (FFD) and sensitivity equation method (SEM).
Abstract: the effects of refining and alkaline chemicals on potential of recycling bleached chemical pulp of bagasse were investigated in this study. Recycling was done until three times. Handsheet properties such as, apparent density, light scattering coefficient, tear index, burst index, breaking length, and fold number according to TAPPI standard were measured. Water retention value also was used to considering the treatments during recycling. Refining enhanced the strength of recycled pulp by increasing fiber flexibility and swelling ability, whereas by applying chemical treatment didn't observe any improvement. The morphology of recycled fiber was considered with scanning electron microscopy (SEM).