Abstract: It is necessary to predict a fatigue crack propagation
life for estimation of structural integrity. Because of an uncertainty
and a randomness of a structural behavior, it is also required to
analyze stochastic characteristics of the fatigue crack propagation life
at a specified fatigue crack size. The essential purpose of this study is to find the effect of load ratio
on probability distribution of the fatigue crack propagation life at a
specified grown crack size and to confirm the good probability
distribution in magnesium alloys under various fatigue load ratio
conditions. To investigate a stochastic crack growth behavior, fatigue
crack propagation experiments are performed in laboratory air under
several conditions of fatigue load ratio using AZ31. By Anderson-Darling test, a goodness-of-fit test for probability
distribution of the fatigue crack propagation life is performed. The
effect of load ratio on variability of fatigue crack propagation life is
also investigated.
Abstract: This study suggests the estimation method of stress
distribution for the beam structures based on TLS (Terrestrial Laser
Scanning). The main components of method are the creation of the
lattices of raw data from TLS to satisfy the suitable condition and
application of CSSI (Cubic Smoothing Spline Interpolation) for
estimating stress distribution. Estimation of stress distribution for the
structural member or the whole structure is one of the important
factors for safety evaluation of the structure. Existing sensors which
include ESG (Electric strain gauge) and LVDT (Linear Variable
Differential Transformer) can be categorized as contact type sensor
which should be installed on the structural members and also there are
various limitations such as the need of separate space where the
network cables are installed and the difficulty of access for sensor
installation in real buildings. To overcome these problems inherent in
the contact type sensors, TLS system of LiDAR (light detection and
ranging), which can measure the displacement of a target in a long
range without the influence of surrounding environment and also get
the whole shape of the structure, has been applied to the field of
structural health monitoring. The important characteristic of TLS
measuring is a formation of point clouds which has many points
including the local coordinate. Point clouds are not linear distribution
but dispersed shape. Thus, to analyze point clouds, the interpolation is
needed vitally. Through formation of averaged lattices and CSSI for
the raw data, the method which can estimate the displacement of
simple beam was developed. Also, the developed method can be
extended to calculate the strain and finally applicable to estimate a
stress distribution of a structural member. To verify the validity of the
method, the loading test on a simple beam was conducted and TLS
measured it. Through a comparison of the estimated stress and
reference stress, the validity of the method is confirmed.
Abstract: Residential buildings consume significant amounts of
energy and produce large amount of emissions and waste. However,
there is a substantial potential for energy savings in this sector which
needs to be evaluated over the life cycle of residential buildings. Life
Cycle Assessment (LCA) methodology has been employed to study
the primary energy uses and associated environmental impacts of
different phases (i.e., product, construction, use, end of life, and
beyond building life) for residential buildings. Four different
alternatives of residential buildings in Vancouver (BC, Canada) with
a 50-year lifespan have been evaluated, including High Rise
Apartment (HRA), Low Rise Apartment (LRA), Single family
Attached House (SAH), and Single family Detached House (SDH).
Life cycle performance of the buildings is evaluated for embodied
energy, embodied environmental impacts, operational energy,
operational environmental impacts, total life-cycle energy, and total
life cycle environmental impacts. Estimation of operational energy
and LCA are performed using DesignBuilder software and Athena
Impact estimator software respectively.
The study results revealed that over the life span of the buildings,
the relationship between the energy use and the environmental
impacts are identical. LRA is found to be the best alternative in terms
of embodied energy use and embodied environmental impacts; while,
HRA showed the best life-cycle performance in terms of minimum
energy use and environmental impacts. Sensitivity analysis has also
been carried out to study the influence of building service lifespan
over 50, 75, and 100 years on the relative significance of embodied
energy and total life cycle energy. The life-cycle energy requirements
for SDH are found to be a significant component among the four
types of residential buildings. The overall disclose that the primary
operations of these buildings accounts for 90% of the total life cycle
energy which far outweighs minor differences in embodied effects
between the buildings.
Abstract: This paper presents an approach for the classification of
an unstructured format description for identification of file formats.
The main contribution of this work is the employment of data mining
techniques to support file format selection with just the unstructured
text description that comprises the most important format features for
a particular organisation. Subsequently, the file format indentification
method employs file format classifier and associated configurations to
support digital preservation experts with an estimation of required file
format. Our goal is to make use of a format specification knowledge
base aggregated from a different Web sources in order to select file
format for a particular institution. Using the naive Bayes method,
the decision support system recommends to an expert, the file format
for his institution. The proposed methods facilitate the selection of
file format and the quality of a digital preservation process. The
presented approach is meant to facilitate decision making for the
preservation of digital content in libraries and archives using domain
expert knowledge and specifications of file formats. To facilitate
decision-making, the aggregated information about the file formats is
presented as a file format vocabulary that comprises most common
terms that are characteristic for all researched formats. The goal is to
suggest a particular file format based on this vocabulary for analysis
by an expert. The sample file format calculation and the calculation
results including probabilities are presented in the evaluation section.
Abstract: This paper presented a study of three algorithms, the
equalization algorithm to equalize the transmission channel with ZF
and MMSE criteria, application of channel Bran A, and adaptive
filtering algorithms LMS and RLS to estimate the parameters of the
equalizer filter, i.e. move to the channel estimation and therefore
reflect the temporal variations of the channel, and reduce the error in
the transmitted signal. So far the performance of the algorithm
equalizer with ZF and MMSE criteria both in the case without noise,
a comparison of performance of the LMS and RLS algorithm.
Abstract: In the past decade, the use of digital image correlation
(DIC) techniques has increased significantly in the area of
experimental mechanics, especially for materials behavior
characterization. This non-contact tool enables full field displacement
and strain measurements over a complete region of interest. The DIC
algorithm requires a random contrast pattern on the surface of the
specimen in order to perform properly. To create this pattern, the
specimen is usually first coated using a white matt paint. Next, a
black random speckle pattern is applied using any suitable method. If
the applied paint coating is too thick, its top surface may not be able
to exactly follow the deformation of the specimen, and consequently,
the strain measurement might be underestimated. In the present
article, a study of the influence of the paint thickness on the strain
underestimation is performed for different strain levels. The results
are then compared to typical paint coating thicknesses applied by
experienced DIC users. A slight strain underestimation was observed
for paint coatings thicker than about 30μm. On the other hand, this
value was found to be uncommonly high compared to coating
thicknesses applied by DIC users.
Abstract: The fatigue life of tubular joints commonly found in
offshore industry is not only dependent on the value of hot-spot stress
(HSS), but is also significantly influenced by the through-thethickness
stress distribution characterized by the degree of bending
(DoB). The determination of DoB values in a tubular joint is essential
for improving the accuracy of fatigue life estimation using the stresslife
(S–N) method and particularly for predicting the fatigue crack
growth based on the fracture mechanics (FM) approach. In the
present paper, data extracted from finite element (FE) analyses of
tubular KT-joints, verified against experimental data and parametric
equations, was used to investigate the effects of geometrical
parameters on DoB values at the crown 0°, saddle, and crown 180°
positions along the weld toe of central brace in tubular KT-joints
subjected to axial loading. Parametric study was followed by a set of
nonlinear regression analyses to derive DoB parametric formulas for
the fatigue analysis of KT-joints under axial loads. The tubular KTjoint
is a quite common joint type found in steel offshore structures.
However, despite the crucial role of the DoB in evaluating the fatigue
performance of tubular joints, this paper is the first attempt to study
and formulate the DoB values in KT-joints.
Abstract: Roles of the vegetation to mitigate the erosion of the
stream bed or to facilitate the deposition of the fine sediments by the
species of the aquatic plants were presented. Field investigation on the
estimation of the change of the bed level and the estimation of the flow
characteristics were performed. The results showed that Phragmites
japonica has the mitigation function of 0.3m-0.4m of the erosion in the
range of higher than 1.0m/s of flow velocity at the vegetated region.
Phragmites communis has the mitigation function of 0.2m-0.3m of the
erosion in the range of higher than 0.7m/s of flow velocity at the
vegetated region. Salix gracilistyla has greater role than Phragmites
japonica and Phragmites communis to sustain the stable channel. It
has the mitigation function of 0.4m-0.5m of the erosion in the range of
higher than 1.4m/s of flow velocity. Miscanthus sacchariflorus has a
weak role compared with that of Phragmites japonica and Salix
gracilistyla, but it has still function for sustaining the stable bed. From
these results, the vegetation has effective roles to mitigate the erosion
or to facilitate the deposition of the stream bed.
Abstract: In statistics parameter theory, usually the
parameter estimations have two kinds, one is the least-square
estimation (LSE), and the other is the best linear unbiased
estimation (BLUE). Due to the determining theorem of
minimum variance unbiased estimator (MVUE), the parameter
estimation of BLUE in linear model is most ideal. But since
the calculations are complicated or the covariance is not
given, people are hardly to get the solution. Therefore, people
prefer to use LSE rather than BLUE. And this substitution
will take some losses. To quantize the losses, many scholars
have presented many kinds of different relative efficiencies in
different views. For the linear weighted regression model, this
paper discusses the relative efficiencies of LSE of β to BLUE
of β. It also defines two new relative efficiencies and gives
their lower bounds.
Abstract: The purpose of the paper is to estimate the US small
wind turbines market potential and forecast the small wind turbines
sales in the US. The forecasting method is based on the application of
the Bass model and the generalized Bass model of innovations
diffusion under replacement purchases. In the work an exponential
distribution is used for modeling of replacement purchases. Only one
parameter of such distribution is determined by average lifetime of
small wind turbines. The identification of the model parameters is
based on nonlinear regression analysis on the basis of the annual
sales statistics which has been published by the American Wind
Energy Association (AWEA) since 2001 up to 2012. The estimation
of the US average market potential of small wind turbines (for
adoption purchases) without account of price changes is 57080
(confidence interval from 49294 to 64866 at P = 0.95) under average
lifetime of wind turbines 15 years, and 62402 (confidence interval
from 54154 to 70648 at P = 0.95) under average lifetime of wind
turbines 20 years. In the first case the explained variance is 90,7%,
while in the second - 91,8%. The effect of the wind turbines price
changes on their sales was estimated using generalized Bass model.
This required a price forecast. To do this, the polynomial regression
function, which is based on the Berkeley Lab statistics, was used. The
estimation of the US average market potential of small wind turbines
(for adoption purchases) in that case is 42542 (confidence interval
from 32863 to 52221 at P = 0.95) under average lifetime of wind
turbines 15 years, and 47426 (confidence interval from 36092 to
58760 at P = 0.95) under average lifetime of wind turbines 20 years.
In the first case the explained variance is 95,3%, while in the second
– 95,3%.
Abstract: This paper presents a rank correlation curve. The
traditional correlation coefficient is valid for both continuous
variables and for integer variables using rank statistics. Since
the correlation coefficient has already been established in rank
statistics by Spearman, such a calculation can be extended to
the correlation curve.
This paper presents two survey questions. The survey
collected non-continuous variables. We will show weak to
moderate correlation. Obviously, one question has a negative
effect on the other. A review of the qualitative literature
can answer which question and why. The rank correlation
curve shows which collection of responses has a positive
slope and which collection of responses has a negative slope.
Such information is unavailable from the flat, ”first-glance”
correlation statistics.
Abstract: All current experimental methods for determination of
stress intensity factors are based on the assumption that the state of
stress near the crack tip is plane stress. Therefore, these methods rely
on strain and displacement measurements made outside the near
crack tip region affected by the three-dimensional effects or by
process zone. In this paper, we develop and validate an experimental
procedure for the evaluation of stress intensity factors from the
measurements of the out-of-plane displacements in the surface area
controlled by 3D effects. The evaluation of stress intensity factors is
possible when the process zone is sufficiently small, and the
displacement field generated by the 3D effects is fully encapsulated
by K-dominance region.
Abstract: The problems arising from unbalanced data sets
generally appear in real world applications. Due to unequal class
distribution, many researchers have found that the performance of
existing classifiers tends to be biased towards the majority class. The
k-nearest neighbors’ nonparametric discriminant analysis is a method
that was proposed for classifying unbalanced classes with good
performance. In this study, the methods of discriminant analysis are
of interest in investigating misclassification error rates for classimbalanced
data of three diabetes risk groups. The purpose of this
study was to compare the classification performance between
parametric discriminant analysis and nonparametric discriminant
analysis in a three-class classification of class-imbalanced data of
diabetes risk groups. Data from a project maintaining healthy
conditions for 599 employees of a government hospital in Bangkok
were obtained for the classification problem. The employees were
divided into three diabetes risk groups: non-risk (90%), risk (5%),
and diabetic (5%). The original data including the variables of
diabetes risk group, age, gender, blood glucose, and BMI were
analyzed and bootstrapped for 50 and 100 samples, 599 observations
per sample, for additional estimation of the misclassification error
rate. Each data set was explored for the departure of multivariate
normality and the equality of covariance matrices of the three risk
groups. Both the original data and the bootstrap samples showed nonnormality
and unequal covariance matrices. The parametric linear
discriminant function, quadratic discriminant function, and the
nonparametric k-nearest neighbors’ discriminant function were
performed over 50 and 100 bootstrap samples and applied to the
original data. Searching the optimal classification rule, the choices of
prior probabilities were set up for both equal proportions (0.33: 0.33:
0.33) and unequal proportions of (0.90:0.05:0.05), (0.80: 0.10: 0.10)
and (0.70, 0.15, 0.15). The results from 50 and 100 bootstrap samples
indicated that the k-nearest neighbors approach when k=3 or k=4 and
the defined prior probabilities of non-risk: risk: diabetic as 0.90:
0.05:0.05 or 0.80:0.10:0.10 gave the smallest error rate of
misclassification. The k-nearest neighbors approach would be
suggested for classifying a three-class-imbalanced data of diabetes
risk groups.
Abstract: Micro-electromechanical system (MEMS)
accelerometers and gyroscopes are suitable for the inertial navigation
system (INS) of many applications due to low price, small
dimensions and light weight. The main disadvantage in a comparison
with classic sensors is a worse long term stability. The estimation
accuracy is mostly affected by the time-dependent growth of inertial
sensor errors, especially the stochastic errors. In order to eliminate
negative effects of these random errors, they must be accurately
modeled. In this paper, the Allan variance technique will be used in
modeling the stochastic errors of the inertial sensors. By performing
a simple operation on the entire length of data, a characteristic curve
is obtained whose inspection provides a systematic characterization
of various random errors contained in the inertial-sensor output data.
Abstract: The seismic risk mitigation from the perspective of
the old buildings stock is truly essential in Algerian urban areas,
particularly those located in seismic prone regions, such as Annaba
city, and which the old buildings present high levels of degradation
associated with no seismic strengthening and/or rehabilitation
concerns. In this sense, the present paper approaches the issue of the
seismic vulnerability assessment of old masonry building stocks
through the adaptation of a simplified methodology developed for a
European context area similar to that of Annaba city, Algeria.
Therefore, this method is used for the first level of seismic
vulnerability assessment of the masonry buildings stock of the old
city center of Annaba. This methodology is based on a vulnerability
index that is suitable for the evaluation of damage and for the
creation of large-scale loss scenarios. Over 380 buildings were
evaluated in accordance with the referred methodology and the
results obtained were then integrated into a Geographical Information
System (GIS) tool. Such results can be used by the Annaba city
council for supporting management decisions, based on a global view
of the site under analysis, which led to more accurate and faster
decisions for the risk mitigation strategies and rehabilitation plans.
Abstract: An adaptive nonparametric method is proposed for
stable real-time detection of seismoacoustic sources in multichannel
C-OTDR systems with a significant number of channels. This
method guarantees given upper boundaries for probabilities of Type I
and Type II errors. Properties of the proposed method are rigorously
proved. The results of practical applications of the proposed method
in a real C-OTDR-system are presented in this report.
Abstract: Latin hypercube designs (LHDs) have been applied in
many computer experiments among the space-filling designs found in
the literature. A LHD can be randomly generated but a randomly
chosen LHD may have bad properties and thus act poorly in
estimation and prediction. There is a connection between Latin
squares and orthogonal arrays (OAs). A Latin square of order s
involves an arrangement of s symbols in s rows and s columns, such
that every symbol occurs once in each row and once in each column
and this exists for every non-negative integer s. In this paper, a
computer program was written to construct orthogonal array-based
Latin hypercube designs (OA-LHDs). Orthogonal arrays (OAs) were
constructed from Latin square of order s and the OAs constructed
were afterward used to construct the desired Latin hypercube designs
for three input variables for use in computer experiments. The LHDs
constructed have better space-filling properties and they can be used
in computer experiments that involve only three input factors.
MATLAB 2012a computer package (www.mathworks.com/) was
used for the development of the program that constructs the designs.
Abstract: The present research work investigates the seismic
response of reinforced concrete (RC) frame building considering the
effect of modeling masonry infill (MI) walls. The seismic behavior of
a residential 6-storey RC frame building, considering and ignoring
the effect of masonry, is numerically investigated using response
spectrum (RS) analysis. The considered herein building is designed
as a moment resisting frame (MRF) system following the Egyptian
code (EC) requirements. Two developed models in terms of bare
frame and infill walls frame are used in the study. Equivalent
diagonal strut methodology is used to represent the behavior of infill
walls, whilst the well-known software package ETABS is used for
implementing all frame models and performing the analysis. The
results of the numerical simulations such as base shear,
displacements, and internal forces for the bare frame as well as the
infill wall frame are presented in a comparative way. The results of
the study indicate that the interaction between infill walls and frames
significantly change the responses of buildings during earthquakes
compared to the results of bare frame building model. Specifically,
the seismic analysis of RC bare frame structure leads to
underestimation of base shear and consequently damage or even
collapse of buildings may occur under strong shakings. On the other
hand, considering infill walls significantly decrease the peak floor
displacements and drifts in both X and Y-directions.
Abstract: We address a new integer frequency offset (IFO)
estimation scheme with an aid of a pilot for orthogonal frequency
division multiplexing systems. After correlating each continual pilot
with a predetermined scattered pilot, the correlation value is again
correlated to alleviate the influence of the timing offset. From
numerical results, it is demonstrated that the influence of the timing
offset on the IFO estimation is significantly decreased.
Abstract: This paper is concerned with knowledge representation
and extraction of fuzzy if-then rules using Interval Type-2
Context-based Fuzzy C-Means clustering (IT2-CFCM) with the aid of
fuzzy granulation. This proposed clustering algorithm is based on
information granulation in the form of IT2 based Fuzzy C-Means
(IT2-FCM) clustering and estimates the cluster centers by preserving
the homogeneity between the clustered patterns from the IT2 contexts
produced in the output space. Furthermore, we can obtain the
automatic knowledge representation in the design of Radial Basis
Function Networks (RBFN), Linguistic Model (LM), and Adaptive
Neuro-Fuzzy Networks (ANFN) from the numerical input-output data
pairs. We shall focus on a design of ANFN in this paper. The
experimental results on an estimation problem of energy performance
reveal that the proposed method showed a good knowledge
representation and performance in comparison with the previous
works.