Abstract: Irradiated material is a typical example of a complex
system with nonlinear coupling between its elements. During
irradiation the radiation damage is developed and this development
has bifurcations and qualitatively different kinds of behavior.
The accumulation of primary defects in irradiated crystals is
considered in frame work of nonlinear evolution of complex system.
The thermo-concentration nonlinear feedback is carried out as a
mechanism of self-oscillation development.
It is shown that there are two ways of the defect density evolution
under stationary irradiation. The first is the accumulation of defects;
defect density monotonically grows and tends to its stationary state
for some system parameters. Another way that takes place for
opportune parameters is the development of self-oscillations of the
defect density.
The stationary state, its stability and type are found. The
bifurcation values of parameters (environment temperature, defect
generation rate, etc.) are obtained. The frequency of the selfoscillation
and the conditions of their development is found and
rated. It is shown that defect density, heat fluxes and temperature
during self-oscillations can reach much higher values than the
expected steady-state values. It can lead to a change of typical
operation and an accident, e.g. for nuclear equipment.
Abstract: We present our ongoing work on the development
of a new quadrotor aerial vehicle which has a tilt-wing
mechanism. The vehicle is capable of take-off/landing in vertical flight mode (VTOL) and flying over long distances in horizontal flight mode. Full dynamic model of the vehicle is derived using
Newton-Euler formulation. Linear and nonlinear controllers for
the stabilization of attitude of the vehicle and control of its
altitude have been designed and implemented via simulations. In particular, an LQR controller has been shown to be quite
effective in the vertical flight mode for all possible yaw angles. A sliding mode controller (SMC) with recursive nature has also
been proposed to stabilize the vehicle-s attitude and altitude. Simulation results show that proposed controllers provide
satisfactory performance in achieving desired maneuvers.
Abstract: In this paper we discuss the effect of unbounded particle interaction operator on particle growth and we study how this can address the choice of appropriate time steps of the numerical simulation. We provide also rigorous mathematical proofs showing that large particles become dominating with increasing time while small particles contribute negligibly. Second, we discuss the efficiency of the algorithm by performing numerical simulations tests and by comparing the simulated solutions with some known analytic solutions to the Smoluchowski equation.
Abstract: The emergence of blended learning has been
influenced by the rapid changes in Higher Education within the last
few years. However, there is a lack of studies that look into the future
of blended learning in the Saudi context. The most likely explanation
is that blended learning is relatively new and, with respect to learning
in general, under-researched. This study addresses this gap and
explores the views of lecturers and students towards the future of
blended learning in Saudi Arabia. This study was informed by the
interpretive paradigm that appears to be most appropriate to
understand and interpret the perceptions of students and instructors
towards a new learning environment. While globally there has been
considerable research on the perceptions of e-learning and blended
learning with its different models, there is plenty of space for further
research specifically in the Arab region, and in Saudi Arabia where
blended learning is now being introduced.
Abstract: The weight constrained shortest path problem
(WCSPP) is one of most several known basic problems in
combinatorial optimization. Because of its importance in many areas
of applications such as computer science, engineering and operations
research, many researchers have extensively studied the WCSPP.
This paper mainly concentrates on the reduction of total search space
for finding WCSP using some existing Genetic Algorithm (GA). For
this purpose, some controlled schemes of genetic operators are
adopted on list chromosome representation. This approach gives a
near optimum solution with smaller elapsed generation than classical
GA technique. From further analysis on the matter, a new
generalized schema theorem is also developed from the philosophy
of Holland-s theorem.
Abstract: In this paper, we propose a reversible watermarking
scheme based on histogram shifting (HS) to embed watermark bits
into the H.264/AVC standard videos by modifying the last nonzero
level in the context adaptive variable length coding (CAVLC) domain.
The proposed method collects all of the last nonzero coefficients (or
called last level coefficient) of 4×4 sub-macro blocks in a macro
block and utilizes predictions for the current last level from the
neighbor block-s last levels to embed watermark bits. The feature of
the proposed method is low computational and has the ability of
reversible recovery. The experimental results have demonstrated that
our proposed scheme has acceptable degradation on video quality and
output bit-rate for most test videos.
Abstract: This work presents the results of a study carried out to
determine the sliding wear behavior and its effect on the process
parameters of components manufactured by direct metal laser
sintering (DMLS). A standard procedure and specimen had been used
in the present study to find the wear behavior. Using Taguchi-s
experimental technique, an orthogonal array of modified L8 had been
developed. Sliding wear testing using pin-on-disk machine was
carried out and analysis of variance (ANOVA) technique was used to
investigate the effect of process parameters and to identify the main
process parameter that influences the properties of wear behavior on
the DMLS components. It has been found that part orientation, one
of the selected process parameter had more influence on wear as
compared to other selected process parameters.
Abstract: This work presents the highly accurate numerical calculation
of the natural frequencies for functionally graded beams with
simply supported boundary conditions. The Timoshenko first order
shear deformation beam theory and the higher order shear deformation
beam theory of Reddy have been applied to the functionally
graded beams analysis. The material property gradient is assumed
to be in the thickness direction. The Hamilton-s principle is utilized
to obtain the dynamic equations of functionally graded beams. The
influences of the volume fraction index and thickness-to-length ratio
on the fundamental frequencies are discussed. Comparison of the
numerical results for the homogeneous beam with Euler-Bernoulli
beam theory results show that the derived model is satisfactory.
Abstract: Business process management (BPM) has become
widely accepted within business community as a means for
improving business performance. However, it is of the highest
importance to incorporate BPM as part of the curriculum at the
university level education in order to achieve the appropriate
acceptance of the method. Goal of the paper is to determine the
current state of education in business process management (BPM) at
the Croatian universities and abroad. It investigates the applied forms
of instruction and teaching methods and gives several proposals for
BPM courses improvement. Since majority of undergraduate and
postgraduate students have limited understanding of business
processes and lack of any practical experience, there is a need for
introducing new teaching approaches. Therefore, we offer some
suggestions for further improvement, among which the introduction
of simulation games environment in BPM education is strongly
recommended.
Abstract: Toughening of polyamide 6 (PA6)/ Nanoclay (NC) nanocomposites with styrene-ethylene/butadiene-styrene copolymer (SEBS) using maleated styrene-ethylene/butadiene-styrene copolymer (mSEBS)/ as a compatibilizer were investigated by blending them in a co-rotating twin-screw extruder. Response surface method of experimental design was used for optimizing the material and processing parameters. Effect of four factors, including SEBS, mSEBS and NC contents as material variables and order of mixing as a processing factor, on toughness of hybrid nanocomposites were studied. All the prepared samples showed ductile behavior and low temperature Izod impact toughness of some of the hybrid nanocomposites demonstrated 900% improvement compared to the PA6 matrix while the modulus showed maximum enhancement of 20% compared to the pristine PA6 resin.
Abstract: Knowing consumers' preferences and perceptions of
the sensory evaluation of drink products are very significant to
manufacturers and retailers alike. With no appropriate sensory
analysis, there is a high risk of market disappointment. This paper
aims to rank the selected coffee products and also to determine the
best of quality attribute through sensory evaluation using fuzzy
decision making model. Three products of coffee drinks were used
for sensory evaluation. Data were collected from thirty judges at a
hypermarket in Kuala Terengganu, Malaysia. The judges were asked
to specify their sensory evaluation in linguistic terms of the quality
attributes of colour, smell, taste and mouth feel for each product and
also the weight of each quality attribute. Five fuzzy linguistic terms
represent the quality attributes were introduced prior analysing. The
judgment membership function and the weights were compared to
rank the products and also to determine the best quality attribute. The
product of Indoc was judged as the first in ranking and 'taste' as the
best quality attribute. These implicate the importance of sensory
evaluation in identifying consumers- preferences and also the
competency of fuzzy approach in decision making.
Abstract: Prestressing in structure increases ratio of load-bearing capacity to weight. Suspendomes are single-layer braced domes reinforced with cable and strut. Prestressing of cables alter value and distribution of stress in structure. In this study two configuration, diamatic and lamella domes is selected. Investigated domes have span of 100m with rise-to-span ratios of 0.1, 0.2, and 0.3. Single layer domes loaded under service load combinations according to ISO code. After geometric nonlinear analysis, models are designed with tubular and I-shaped sections then reinforced with cable and strut and converted to suspendomes. Displacements and stresses of some groups of nodes and elements in all of single-layer domes and suspendomes for three load combinations, symmetric snow, asymmetric snow and wind are compared. Variation due to suspending system is investigated. Suspendomes are redesigned and minimum possible weight after addition of cable and strut is obtained.
Abstract: Subjective loneliness describes people who feel a
disagreeable or unacceptable lack of meaningful social relationships,
both at the quantitative and qualitative level. The studies to be
presented tested an Italian 18-items self-report loneliness measure,
that included items adapted from scales previously developed,
namely a short version of the UCLA (Russell, Peplau and Cutrona,
1980), and the 11-items Loneliness scale by De Jong-Gierveld &
Kamphuis (JGLS; 1985). The studies aimed at testing the developed
scale and at verifying whether loneliness is better conceptualized as a
unidimensional (so-called 'general loneliness') or a bidimensional
construct, namely comprising the distinct facets of social and
emotional loneliness. The loneliness questionnaire included 2 singleitem
criterion measures of sad mood, and social contact, and asked
participants to supply information on a number of socio-demographic
variables. Factorial analyses of responses obtained in two
preliminary studies, with 59 and 143 Italian participants respectively,
showed good factor loadings and subscale reliability and confirmed
that perceived loneliness has clearly two components, a social and an
emotional one, the latter measured by two subscales, a 7-item
'general' loneliness subscale derived from UCLA, and a 6–item
'emotional' scale included in the JGLS. Results further showed that
type and amount of loneliness are related, negatively, to frequency of
social contacts, and, positively, to sad mood. In a third study data
were obtained from a nation-wide sample of 9.097 Italian subjects,
12 to about 70 year-olds, who filled the test on-line, on the Italian
web site of a large-audience magazine, Focus. The results again
confirmed the reliability of the component subscales, namely social,
emotional, and 'general' loneliness, and showed that they were
highly correlated with each other, especially the latter two.
Loneliness scores were significantly predicted by sex, age, education
level, sad mood and social contact, and, less so, by other variables –
e.g., geographical area and profession. The scale validity was
confirmed by the results of a fourth study, with elderly men and
women (N 105) living at home or in residential care units. The three
subscales were significantly related, among others, to depression, and
to various measures of the extension of, and satisfaction with, social
contacts with relatives and friends. Finally, a fifth study with 315
career-starters showed that social and emotional loneliness correlate
with life satisfaction, and with measures of emotional intelligence.
Altogether the results showed a good validity and reliability in the
tested samples of the entire scale, and of its components.
Abstract: In the management of industrial waste, conversion from the use of paper invoices to electronic forms is currently under way in developed countries. Difficulties in such computerization include the lack of synchronization between the actual goods and the corresponding data managed by the server. Consequently, a system which utilizes the incorporation of a QR code in connection with the waste material has been developed. The code is read at each stage, from discharge until disposal, and progress at each stage can be easily reported. This system can be linked with Japanese public digital authentication service of waste, taking advantage of its good points, and can be used to submit reports to the regulatory authorities. Its usefulness was confirmed by a verification test, and put into actual practice.
Abstract: The purpose of this research is to disentangle and
validate the underlying factorial-structure of Ecotourism Experiential
Value (EEV) measurement scale and subsequently investigate its
psychometric properties. The analysis was based on a sample of 225
eco-tourists, collected at the vicinity of Taman Negara National Park
(TNNP) via interviewer-administered questionnaire. Exploratory
factor analysis (EFA) was performed to determine the factorial
structure of EEV. Subsequently, to confirm and validate the factorial
structure and assess the psychometric properties of EEV,
confirmatory factor analysis (CFA) was executed. In addition, to
establish the nomological validity of EEV a structural model was
developed to examine the effect of EEV on Total Eco-tourist
Experience Quality (TEEQ). It is unveiled that EEV is a secondorder
six-factorial structure construct and it scale has adequately met
the psychometric criteria, thus could permit interpretation of results
confidently. The findings have important implications for future
research directions and management of ecotourism destination.
Abstract: The objective is to fabricate organic light emitting
diode and to study its degradation process in atmosphere condition in
which PFO as an emitting material and PEDOT:PSS as a hole
injecting material were used on ITO substrate. Thus degradation
process of the OLED was studied upon its current-voltage
characteristic. By fabricating this OLED and obtaining blue light and
analysis of current-voltage characteristic during the time after
fabrication, it was observed that the current of the OLED was
exponentially decreased. Current reduction during the initial hours of
fabrication was outstanding and after few days its reduction rate was
dropped significantly, while the diode was dying.
Abstract: Nowadays, the plant location selection has a critical
impact on the performance of numerous companies. In this paper, a
methodology is presented to solve this problem. The three decision
making methods, namely Delphi, AHP and improved VIKOR, are
hybridized in order to make the best use of information available
based on the decision makers or experts. In this respect, the aim of
using Delphi is to select the most influential criteria by a few decision
makers. The AHP is utilized to give weights of the selected criteria.
Finally, the improved VIKOR method is applied to rank alternatives.
At the end of paper, an application example demonstrates the
applicability of the proposed methodology.
Abstract: This paper presents a numerical analysis of the
seismic behaviour of earth dams. Analysis is conducted for the solid
phase. It may correspond to the response of the dam before water
filling. Analysis is conducted for a simple case which concerns the
elastic response of the dam. Numerical analyses are conducted using
the FLAC3D program. The behaviour of the Shell and core of the
dam and the foundation behaviour is assumed to be elastic. Result
shows the influence of the variation of the shear modulus of the core
and shell on the seismic amplification of the dam. It can be observed
that the variation of the shearing modulus of the core leads to a
moderate increase in the dynamic amplification and the increase in
the shell shearing modulus leads to a significant increase in the
dynamic amplification.
Abstract: Aspect of visual perception occupies a central position
in shaping the physical structure of a city. This paper discusses the
visual characteristics of utopian cities and their impact on the shaping
of real urban structures. Utopian examples of cities will not be
discussed in terms of social and sociological conditions, but rather
the emphasis is on urban utopias and ideal cities that have achieved
or have had potential impact on the shape of the physical structure of
Nikšić. It is a Renaissance-Baroque period with a touch of classicism.
The paper’s emphasis is on the physical dimension, not excluding the
importance of social equilibrium, studies of which are dating back to
Aristotle, Plato, Thomas More, Robert Owen, Tommaso Campanella
and others. The emphasis is on urban utopias and their impact on the
development of sustainable physical structure of a real city in the
context of visual perception. In the case of Nikšić, this paper
identifies the common features of a real city and a utopian city, as
well as criteria for sustainable urban development in the context of
visual achievement.
Abstract: A new technique to quantify the differential mode
delay (DMD) in multimode fiber (MMF) is been presented. The
technique measures DMD based on angular launch and
measurements of the difference in modal delay using variable
apertures at the fiber face. The result of the angular spatial filtering
revealed less excitation of higher order modes when the laser beam is
filtered at higher angles. This result would indicate that DMD
profiles would experience a data pattern dependency.