Abstract: This study investigates the effects of the lead angle
and chip thickness variation on surface roughness during the
machining of compacted graphite iron using ceramic cutting tools
under dry cutting conditions. Analytical models were developed for
predicting the surface roughness values of the specimens after the
face milling process. Experimental data was collected and imported
to the artificial neural network model. A multilayer perceptron model
was used with the back propagation algorithm employing the input
parameters of lead angle, cutting speed and feed rate in connection
with chip thickness. Furthermore, analysis of variance was employed
to determine the effects of the cutting parameters on surface
roughness. Artificial neural network and regression analysis were
used to predict surface roughness. The values thus predicted were
compared with the collected experimental data, and the
corresponding percentage error was computed. Analysis results
revealed that the lead angle is the dominant factor affecting surface
roughness. Experimental results indicated an improvement in the
surface roughness value with decreasing lead angle value from 88° to
45°.
Abstract: Evidence shows that start-ups success is positively
correlated with the launch of the first product. However, new ventures
are seldom able to acquire abundant resources for new product
development (NPD), which means that entrepreneurs may depend on
personal creativity instead of physical investments to achieve and
accelerate innovation speed. This study accentuates the role of
entrepreneurial bricolage, which defined as making do by applying
combinations of the resources at hand to new problems and
opportunities, in the relations of creative self-efficacy and innovation
speed. This study uses the multiple regression analysis to test the
hypotheses in a sample of 203 start-ups operating in various creative
markets in Taiwan. Results reveal that creative self-efficacy is
positively and directly associated with innovation speed, whereas
entrepreneurial bricolage plays a full mediator. These findings offer
important theoretical and practical implications.
Abstract: This paper presents the ‘Eye Ball Motion Controlled
Wheelchair using IR Sensors’ for the elderly and differently abled
people. In this eye tracking based technology, three Proximity
Infrared (IR) sensor modules are mounted on an eye frame to trace
the movement of the iris. Since, IR sensors detect only white objects;
a unique sequence of digital bits is generated corresponding to each
eye movement. These signals are then processed via a micro
controller IC (PIC18F452) to control the motors of the wheelchair.
The potential and efficiency of previously developed rehabilitation
systems that use head motion, chin control, sip-n-puff control, voice
recognition, and EEG signals variedly have also been explored in
detail. They were found to be inconvenient as they served either
limited usability or non-affordability. After multiple regression
analyses, the proposed design was developed as a cost-effective,
flexible and stream-lined alternative for people who have trouble
adopting conventional assistive technologies.
Abstract: This study, for its research subjects, uses patients who
had undergone total knee replacement surgery from the database of the
National Health Insurance Administration. Through the review of
literatures and the interviews with physicians, important factors are
selected after careful screening. Then using Cross Entropy Method,
Genetic Algorithm Logistic Regression, and Particle Swarm
Optimization, the weight of each factor is calculated and obtained. In
the meantime, Excel VBA and Case Based Reasoning are combined
and adopted to evaluate the system. Results show no significant
difference found through Genetic Algorithm Logistic Regression and
Particle Swarm Optimization with over 97% accuracy in both
methods. Both ROC areas are above 0.87. This study can provide
critical reference to medical personnel as clinical assessment to
effectively enhance medical care quality and efficiency, prevent
unnecessary waste, and provide practical advantages to resource
allocation to medical institutes.
Abstract: Hemoglobin (HB) indicates anemia level and by
extension may reflect the nutritional level and perhaps the immunity
of an individual. Some antiretroviral drugs like Zidovudine are
known to cause anemia in people living with HIV/AIDS (PLWHA).
A cross sectional study using demographic data and blood specimen
from 218 female commercial sex workers attending antiretroviral
therapy (ART) clinics was conducted between December, 2009 and
July, 2011 to assess the effect of zidovudine on hematologic, and
RNA viral load of female sex workers receiving antiretroviral
treatment in north western Nigeria. Anemia is a common and serious
complication of both HIV infection and its treatment. In the setting of
HIV infection, anemia has been associated with decreased quality of
life, functional status, and survival. Antiretroviral therapy,
particularly the highly active antiretroviral therapy (HAART), has
been associated with a decrease in the incidence and severity of
anemia in HIV-infected patients who have received a HAART
regimen for at least 1 year. In this study, result has shown that of the
218 patients, 26 with hemoglobin count between 5.1 – 10g/dl were
observed to have the highest viral load count of 300,000 –
350,000copies/ml. It was also observed that most patients (190) with
HB of 10.1 – 15.0g/dl had viral load count of 200,000 – 250,000
copies /ml. An inverse relationship therefore exists i.e. the lower the
hemoglobin level, the higher the viral load count even though the test
statistics did not show any significance between the two (P = 0.206).
This shows that multivariate logistic regression analysis
demonstrated that anemia was associated with a CD4 + cell count
below 50/μL, female sex workers with a viral load above 100,000
copies/mL, who use zidovudine.
Severe anemia was less prevalent in this study population than in
historical comparators; however, mild to moderate anemia rates
remain high. The study therefore recommends that hematological and
virologic parameters be monitored closely in patients receiving first
line ART regimen.
Abstract: In the present study, response surface methodology has been used to optimize turn-assisted deep cold rolling process of AISI 4140 steel. A regression model is developed to predict surface hardness and surface roughness using response surface methodology and central composite design. In the development of predictive model, deep cold rolling force, ball diameter, initial roughness of the workpiece, and number of tool passes are considered as model variables. The rolling force and the ball diameter are the significant factors on the surface hardness and ball diameter and numbers of tool passes are found to be significant for surface roughness. The predicted surface hardness and surface roughness values and the subsequent verification experiments under the optimal operating conditions confirmed the validity of the predicted model. The absolute average error between the experimental and predicted values at the optimal combination of parameter settings for surface hardness and surface roughness is calculated as 0.16% and 1.58% respectively. Using the optimal processing parameters, the surface hardness is improved from 225 to 306 HV, which resulted in an increase in the near surface hardness by about 36% and the surface roughness is improved from 4.84µm to 0.252 µm, which resulted in decrease in the surface roughness by about 95%. The depth of compression is found to be more than 300µm from the microstructure analysis and this is in correlation with the results obtained from the microhardness measurements. Taylor hobson talysurf tester, micro vickers hardness tester, optical microscopy and X-ray diffractometer are used to characterize the modified surface layer.
Abstract: In recent years, there has been a decline in physical
activity among adults. Motivation has been shown to be a crucial
factor in maintaining physical activity. The purpose of this study was
to whether PA motives measured by the Physical Activity and
Leisure Motivation Scale PALMS predicted the actual amount of PA
at a later time to provide evidence for the construct validity of the
PALMS. A quantitative, cross-sectional descriptive research design
was employed. The Demographic Form, PALMS, and International
Physical Activity Questionnaire Short form (IPAQ-S) questionnaires
were used to assess motives and amount for physical activity in
adults on two occasions. A sample of 489 male undergraduate
students aged 18 to 25 years (mean ±SD; 22.30±8.13 years) took part
in the study. Participants were divided into three types of activities,
namely exercise, racquet sport, and team sports and female
participants only took part in one type of activity, namely team
sports. After 14 weeks, all 489 undergraduate students who had filled
in the initial questionnaire (Occasion 1) received the questionnaire
via email (Occasion 2). Of the 489 students, 378 males emailed back
the completed questionnaire. The results showed that not only were
pertinent sub-scales of PALMS positively related to amount of
physical activity, but separate regression analyses showed the
positive predictive effect of PALMS motives for amount of physical
activity for each type of physical activity among participants. This
study supported the construct validity of the PALMS by showing that
the motives measured by PALMS did predict amount of PA. This
information can be obtained to match people with specific sport or
activity which in turn could potentially promote longer adherence to
the specific activity.
Abstract: In this paper, we present a model-based regression test
suite reducing approach that uses EFSM model dependence analysis
and probability-driven greedy algorithm to reduce software regression
test suites. The approach automatically identifies the difference
between the original model and the modified model as a set of
elementary model modifications. The EFSM dependence analysis is
performed for each elementary modification to reduce the regression
test suite, and then the probability-driven greedy algorithm is adopted
to select the minimum set of test cases from the reduced regression test
suite that cover all interaction patterns. Our initial experience shows
that the approach may significantly reduce the size of regression test
suites.
Abstract: The venture capital becomes more and more advanced
and effective source of the innovation project financing, connected
with a high-risk level. In the developed countries, it plays a key role
in transforming innovation projects into successful businesses and
creating the prosperity of the modern economy. In Russia, there are
many necessary preconditions for creation of the effective venture
investment system: the network of the public institutes for innovation
financing operates; there is a significant number of the small and
medium-sized enterprises, capable to sell production with good
market potential. However, the current system does not confirm the
necessary level of efficiency in practice that can be substantially
explained by the absence of the accurate plan of action to form the
national venture model and by the lack of experience of successful
venture deals with profitable exits in Russian economy. This paper
studies the influence of various factors on the venture industry
development by the example of the IT-sector in Russia. The choice of
the sector is based on the fact, that this segment is the main driver of
the venture capital market growth in Russia, and the necessary set of
data exists. The size of investment of the second round is used as the
dependent variable. To analyse the influence of the previous round,
such determinant as the volume of the previous (first) round
investments is used. There is also used a dummy variable in
regression to examine that the participation of an investor with high
reputation and experience in the previous round can influence the size
of the next investment round. The regression analysis of short-term
interrelations between studied variables reveals prevailing influence
of the volume of the first round investments on the venture
investments volume of the second round. The most important
determinant of the value of the second-round investment is the value
of first–round investment, so it means that the most competitive on
the Russian market are the start-up teams that can attract more money
on the start, and the target market growth is not the factor of crucial
importance. This supports the point of view that VC in Russia is
driven by endogenous factors and not by exogenous ones that are
based on global market growth.
Abstract: There is not much effective guideline on development of design parameters selection on spring back for advanced high strength steel sheet metal in U-channel process during cold forming process. This paper presents the development of predictive model for spring back in U-channel process on advanced high strength steel sheet employing Response Surface Methodology (RSM). The experimental was performed on dual phase steel sheet, DP590 in Uchannel forming process while design of experiment (DoE) approach was used to investigates the effects of four factors namely blank holder force (BHF), clearance (C) and punch travel (Tp) and rolling direction (R) were used as input parameters using two level values by applying Full Factorial design (24 ). From a statistical analysis of variant (ANOVA), result showed that blank holder force (BHF), clearance (C) and punch travel (Tp) displayed significant effect on spring back of flange angle (β2 ) and wall opening angle (β1 ), while rolling direction (R) factor is insignificant. The significant parameters are optimized in order to reduce the spring back behavior using Central Composite Design (CCD) in RSM and the optimum parameters were determined. A regression model for spring back was developed. The effect of individual parameters and their response was also evaluated. The results obtained from optimum model are in agreement with the experimental values.
Abstract: Community integration is a construct that an
increasing body of research has shown to have a significant impact
on the wellbeing and recovery of people with psychiatric problems.
However, there are few studies that explore which factors can be
associated and predict community integration. Moreover, community
integration has been mostly studied in minority groups, and current
literature on the definition and manifestation of community
integration in the general population is scarcer. Thus, the current
study aims to characterize community integration and explore
possible predictor variables in a sample of participants with
psychiatric problems (PP, N=183) and a sample of participants from
the general population (GP, N=211).
Results show that people with psychiatric problems present above
average values of community integration, but are significantly lower
than their healthy counterparts. It was also possible to observe that
community integration does not vary in terms of the sociodemographic
characteristics of both groups in this study. Correlation
and multiple regression showed that, among several variables that
literature present as relevant in the community integration process,
only three variables emerged as having the most explanatory value in
community integration of both groups: sense of community, basic
needs satisfaction and submission. These results also shown that
those variables have increased explanatory power in the PP sample,
which leads us to emphasize the need to address this issue in future
studies and increase the understanding of the factors that can be
involved in the promotion of community integration, in order to
devise more effective interventions in this field.
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: Auditory hallucinations among the most invalidating
and distressing experiences reported by patients diagnosed with
schizophrenia, leading to feelings of powerlessness and helplessness
towards their illness. In more severe cases, these auditory
hallucinations can take the form of commanding voices, which are
often related to high suicidality rates in these patients. Several
authors propose that the meanings attributed to the hallucinatory
experience, rather than characteristics like form and content, can be
determinant in patients’ reactions to hallucinatory activity,
particularly in the case of voice-hearing experiences. In this study, 48
patients diagnosed with paranoid schizophrenia presenting auditory
hallucinations were studied. Multiple regression analyses were
computed to study the influence of several developmental aspects,
such as family and social dynamics, bullying, depression, and sociocognitive
variables on the auditory hallucinations, on patients’
attributions and relationships with their voices, and on the resulting
invalidation of hallucinatory experience. Overall, results showed how
relationships with voices can mirror several aspects of interpersonal
relationship with others, and how self-schemas, depression and actual
social relationships help shaping the voice-hearing experience. Early
experiences of victimization and submission help predict the
attributions of omnipotence of the voices, and increased hostility
from parents seems to increase the malevolence of the voices,
suggesting that socio-cognitive factors can significantly contribute to
the etiology and maintenance of auditory hallucinations. The
understanding of the characteristics of auditory hallucinations and the
relationships patients established with their voices can allow the
development of more promising therapeutic interventions that can be
more effective in decreasing invalidation caused by this devastating
mental illness.
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: Al6061 alloy base matrix, reinforced with particles of
silicon carbide (10 wt %) and Graphite powder (1wt%), known as
hybrid composites have been fabricated by liquid metallurgy route
(stir casting technique) and optimized at different parameters like
applied load, sliding speed and sliding distance by taguchi method. A
plan of experiment generated through taguchi technique was used to
perform experiments based on L27 orthogonal array. The developed
ANOVA and regression equations are used to find the optimum
coefficient of friction and wear under the influence of applied load,
sliding speed and sliding distance. On the basis of “smaller the best”
the dry sliding wear resistance was analysed and finally confirmation
tests were carried out to verify the experimental results.
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: In this paper, a model is proposed to determine the life
distribution parameters of the useful life region for the PV system
utilizing a combination of non-parametric and linear regression
analysis for the failure data of these systems. Results showed that this
method is dependable for analyzing failure time data for such reliable
systems when the data is scarce.
Abstract: Prosperity of electronic equipment in photocopying
environment not only has improved work efficiency, but also has
changed indoor air quality. Considering the number of photocopying
employed, indoor air quality might be worse than in general office
environments. Determining the contribution from any type of
equipment to indoor air pollution is a complex matter. Non-methane
hydrocarbons are known to have an important role on air quality due
to their high reactivity. The presence of hazardous pollutants in
indoor air has been detected in one photocopying shop in Novi Sad,
Serbia. Air samples were collected and analyzed for five days, during
8-hr working time in three time intervals, whereas three different
sampling points were determined. Using multiple linear regression
model and software package STATISTICA 10 the concentrations of
occupational hazards and microclimates parameters were mutually
correlated. Based on the obtained multiple coefficients of
determination (0.3751, 0.2389 and 0.1975), a weak positive
correlation between the observed variables was determined. Small
values of parameter F indicated that there was no statistically
significant difference between the concentration levels of nonmethane
hydrocarbons and microclimates parameters. The results
showed that variable could be presented by the general regression
model: y = b0 + b1xi1+ b2xi2. Obtained regression equations allow to
measure the quantitative agreement between the variables and thus
obtain more accurate knowledge of their mutual relations.
Abstract: This paper analyzes the conceptual framework of three
statistical methods, multiple regression, path analysis, and structural
equation models. When establishing research model of the statistical
modeling of complex social phenomenon, it is important to know the
strengths and limitations of three statistical models. This study
explored the character, strength, and limitation of each modeling and
suggested some strategies for accurate explaining or predicting the
causal relationships among variables. Especially, on the studying of
depression or mental health, the common mistakes of research
modeling were discussed.