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: Cellular networks provide voice and data services to the users with mobility. To deliver services to the mobile users, the cellular network is capable of tracking the locations of the users, and allowing user movement during the conversations. These capabilities are achieved by the location management. Location management in mobile communication systems is concerned with those network functions necessary to allow the users to be reached wherever they are in the network coverage area. In a cellular network, a service coverage area is divided into smaller areas of hexagonal shape, referred to as cells. The cellular concept was introduced to reuse the radio frequency. Continued expansion of cellular networks, coupled with an increasingly restricted mobile spectrum, has established the reduction of communication overhead as a highly important issue. Much of this traffic is used in determining the precise location of individual users when relaying calls, with the field of location management aiming to reduce this overhead through prediction of user location. This paper describes and compares various location management schemes in the cellular networks.
Abstract: High-voltage power transmission lines are the back
bone of electrical power utilities. The stability and continuous
monitoring of this critical infrastructure is pivotal. Nine-Sigma
representing Eskom Holding SOC limited, South Africa has a major
problem on proactive detection of fallen power lines and real time
sagging measurement together with slipping of such conductors. The
main objective of this research is to innovate RFID technology to
solve this challenge. Various options and technologies such as GPS,
PLC, image processing, MR sensors and etc., have been reviewed
and draw backs were made. The potential of RFID to give precision
measurement will be observed and presented. The future research
will look at magnetic and electrical interference as well as corona
effect on the technology.
Abstract: This paper proposes a synchronized random switching frequency pulse width modulation (SRSFPWM). In this technique, the clock signal is used to control the random noise frequency which is produced by the feedback voltage of a hysteresis circuit. These make the triangular carrier frequency equaling to the random noise frequency in each switching period with the symmetrical positive and negative slopes of triangular carrier. Therefore, there is no error voltage in PWM signal. The PSpice simulated results shown the proposed technique improved the performance in case of low frequency harmonics of PWM signal comparing with conventional random switching frequency PWM.
Abstract: A computationally simple approach of model order
reduction for single input single output (SISO) and linear timeinvariant
discrete systems modeled in frequency domain is proposed
in this paper. Denominator of the reduced order model is determined
using fuzzy C-means clustering while the numerator parameters are
found by matching time moments and Markov parameters of high
order system.
Abstract: The theoretical investigation is carried out to describe
the effect of increase of pressure waves amplitude in clean and bubbly liquid. The goal of the work is to capture the regime of multiple magnification of acoustic and shock waves in the liquid,
which enables to get appropriate conditions to enlarge collapses of
micro-bubbles. The influence of boundary conditions and frequency
of the governing acoustic field is studied for the case of the
cylindrical acoustic resonator. It has been observed the formation of
standing waves with large amplitude at resonant frequencies. The
interaction of the compression wave with gas and vapor bubbles is
investigated for the convergent channel. It is shown theoretically that
the chemical reactions, which occur inside gas bubbles, provide additional impulse to the wave, that affect strongly on the collapses
of the vapor bubbles
Abstract: This paper presents a recognition system for isolated
words like robot commands. It’s carried out by Time Delay Neural
Networks; TDNN. To teleoperate a robot for specific tasks as turn,
close, etc… In industrial environment and taking into account the
noise coming from the machine. The choice of TDNN is based on its
generalization in terms of accuracy, in more it acts as a filter that
allows the passage of certain desirable frequency characteristics of
speech; the goal is to determine the parameters of this filter for
making an adaptable system to the variability of speech signal and to
noise especially, for this the back propagation technique was used in
learning phase. The approach was applied on commands pronounced
in two languages separately: The French and Arabic. The results for
two test bases of 300 spoken words for each one are 87%, 97.6% in
neutral environment and 77.67%, 92.67% when the white Gaussian
noisy was added with a SNR of 35 dB.
Abstract: A wireless power transfer system can attribute to the
fields in robot, aviation and space in which lightening the weight of
device and improving the movement play an important role. A
wireless power transfer system was investigated to overcome the
inconvenience of using power cable. Especially a wireless power
transfer technology is important element for mobile robots. We
proposed the wireless power transfer system of the half-bridge
resonant converter with the frequency tracking and optimized
power transfer control unit. And the possibility of the application
and development system was verified through the experiment with
LED loads.
Abstract: In this paper the authors propose a flexible electronic solution, to improve the energetic efficiency of a thermo plant. This is achieved by replacing the mechanical gear box, placed traditionally between a gas turbine and a synchronous generator; by a power electronic converter. After reminding problematic of gear boxes and interest of a proposed electronic solution in high power plants, the authors describe a new control strategy for an indirect frequency converter, which is characterized by its high efficiency due to the use of SWM: Square Wave Modulation. The main advantage of this mode is the quasi absence of switching losses. A control method is also proposed to resolve some problems incurred by using square wave modulation, in particular to reduce the harmonics distortion of the output inverter voltage and current. Simulation examples as well as experimental results are included.
Abstract: This paper deals with automatic sentence modality
recognition in French. In this work, only prosodic features are
considered. The sentences are recognized according to the three
following modalities: declarative, interrogative and exclamatory
sentences. This information will be used to animate a talking head for
deaf and hearing-impaired children. We first statistically study a real
radio corpus in order to assess the feasibility of the automatic
modeling of sentence types. Then, we test two sets of prosodic
features as well as two different classifiers and their combination. We
further focus our attention on questions recognition, as this modality
is certainly the most important one for the target application.
Abstract: The aim of this study is to discover secondary school students’ perceptions related to information technologies and the connections between concepts in their cognitive structures. A word association test consisting of six concepts related to information technologies is used to collect data from 244 secondary school students. Concept maps that present students’ cognitive structures are drawn with the help of frequency data. Data are analyzed and interpreted according to the connections obtained as a result of the concept maps. It is determined students associate most with these concepts—computer, Internet, and communication of the given concepts, and associate least with these concepts—computer-assisted education and information technologies. These results show the concepts, Internet, communication, and computer, are an important part of students’ cognitive structures. In addition, students mostly answer computer, phone, game, Internet and Facebook as the key concepts. These answers show students regard information technologies as a means for entertainment and free time activity, not as a means for education.
Abstract: The range of the output power is a very important and evident limitation of two-level inverters. In order to overcome this disadvantage, multilevel inverters are introduced. Recently, Cascade H-Bridge inverters have emerged as one of the popular converter topologies used in numerous industrial applications. The modulation switching strategies such as phase shifted carrier based Pulse Width Modulation (PWM) technique and Stair case modulation with Selective Harmonic Elimination (SHE) PWM technique are generally used. NR method is used to solve highly non linear transcendental equations which are formed by SHEPWM method. Generally NR method has a drawback of requiring good initial guess but in this paper a new approach is implemented for NR method with any random initial guess. A three phase CHB 11-level inverter is chosen for analysis. MATLAB/SIMULINK programming environment and harmonic profiles are compared. Finally this paper presents a method at fundamental switching frequency with least % THDV.
Abstract: Today modern simulations solutions in the wind turbine industry have achieved a high degree of complexity and detail in result. Limitations exist when it is time to validate model results against measurements. Regarding Model validation it is of special interest to identify mode frequencies and to differentiate them from the different excitations. A wind turbine is a complex device and measurements regarding any part of the assembly show a lot of noise. Input excitations are difficult or even impossible to measure due to the stochastic nature of the environment. Traditional techniques for frequency analysis or features extraction are widely used to analyze wind turbine sensor signals, but have several limitations specially attending to non stationary signals (Events). A new technique based on autoregresive analysis techniques is introduced here for a specific application, a comparison and examples related to different events in the wind turbine operations are presented.
Abstract: This paper reports the results of an experimental study
conducted to characterise the gas-liquid multiphase flows
experienced within a vertical riser transporting a range of gas-liquid
flow rates. The scale experiments were performed using an
air/silicone oil mixture within a 6 m long riser. The superficial air
velocities studied ranged from 0.047 to 2.836 m/ s, whilst
maintaining a liquid superficial velocity at 0.047 m/ s. Measurements
of the mean cross-sectional and time average radial void fraction
were obtained using a wire mesh sensor (WMS). The data were
recorded at an acquisition frequency of 1000 Hz over an interval of
60 seconds. For the range of flow conditions studied, the average
void fraction was observed to vary between 0.1 and 0.9. An analysis
of the data collected concluded that the observed void fraction was
strongly affected by the superficial gas velocity, whereby the higher
the superficial gas velocity, the higher was the observed average void
fraction. The average void fraction distributions observed were in
good agreement with the results obtained by other researchers. When
the air-silicone oil flows were fully developed reasonably symmetric
profiles were observed, with the shape of the symmetry profile being
strongly dependent on the superficial gas velocity.
Abstract: In this paper, all-optical signal processors that perform
both microwave mixing and bandpass filtering in a radio-over-fiber
(RoF) link are presented. The key device is a Mach-Zehnder
modulator (MZM) which performs all-optical microwave mixing. An
up-converted microwave signal is obtained and other unwanted
frequency components are suppressed at the end of the fiber span.
Abstract: In this paper we illuminate a frequency domain based
classification method for video scenes. Videos from certain topical
areas often contain activities with repeating movements. Sports
videos, home improvement videos, or videos showing mechanical
motion are some example areas. Assessing main and side frequencies
of each repeating movement gives rise to the motion type. We
obtain the frequency domain by transforming spatio-temporal motion
trajectories. Further on we explain how to compute frequency features
for video clips and how to use them for classifying. The focus of
the experimental phase is on transforms utilized for our system.
By comparing various transforms, experiments show the optimal
transform for a motion frequency based approach.
Abstract: The aim of this paper is to emphasize and alleviate the effect of phase noise due to imperfect local oscillators on the performances of a Multi-Carrier CDMA system. After the cancellation of Common Phase Error (CPE), an iterative approach is introduced which iteratively estimates Inter-Carrier Interference (ICI) components in the frequency domain and cancels their contribution in the time domain. Simulation are conducted in order to investigate the achievable performances for several parameters, such as the spreading factor, the modulation order, the phase noise power and the transmission Signal-to-Noise Ratio.
Abstract: This paper presented a proposed design for
transcutaneous inductive powering links. The design used to transfer
power and data to the implanted devices such as implanted
Microsystems to stimulate and monitoring the nerves and muscles.
The system operated with low band frequency 13.56 MHZ according
to industrial- scientific – medical (ISM) band to avoid the tissue
heating. For external part, the modulation index is 13 % and the
modulation rate 7.3% with data rate 1 Mbit/s assuming Tbit=1us. The
system has been designed using 0.35-μm fabricated CMOS
technology. The mathematical model is given and the design is
simulated using OrCAD P Spice 16.2 software tool and for real-time
simulation the electronic workbench MULISIM 11 has been used.
The novel circular plane (pancake) coils was simulated using
ANSOFT- HFss software.
Abstract: There is an ongoing controversy in the literature related
to the biological effects of weak, low frequency electromagnetic
fields. The physical arguments and interpretation of the experimental
evidence are inconsistent, where some physical arguments and
experimental demonstrations tend to reject the likelihood of any
effect of the fields at extremely low level. The problem arises of
explaining, how the low-energy influences of weak magnetic fields
can compete with the thermal and electrical noise of cells at normal
temperature using the theoretical studies. The magnetoreception in
animals involve radical pair mechanism. The same mechanism has
been shown to be involved in the circadian rhythm synchronization in
mammals. These reactions can be influenced by the weak magnetic
fields. Hence, it is postulated the biological clock can be affected
by weak magnetic fields and these disruptions to the rhythm can
cause adverse biological effects. In this paper, likelihood of altering
the biological clock via the radical pair mechanism is analyzed to
simplify these studies of controversy.
Abstract: One of the disadvantages of using OFDM is the larger
peak to averaged power ratio (PAPR) in its time domain signal. The
larger PAPR signal would course the fatal degradation of bit error
rate performance (BER) due to the inter-modulation noise in the nonlinear
channel. This paper proposes an improved DSI (Dummy
Sequence Insertion) method, which can achieve the better PAPR and
BER performances. The feature of proposed method is to optimize
the phase of each dummy sub-carrier so as to reduce the PAPR
performance by changing all predetermined phase coefficients in the
time domain signal, which is calculated for data sub-carriers and
dummy sub-carriers separately. To achieve the better PAPR
performance, this paper also proposes to employ the time-frequency
domain swapping algorithm for fine adjustment of phase coefficient
of the dummy subcarriers, which can achieve the less complexity of
processing and achieves the better PAPR and BER performances
than those for the conventional DSI method. This paper presents
various computer simulation results to verify the effectiveness of
proposed method as comparing with the conventional methods in the
non-linear channel.