Abstract: In this paper, we consider the analysis of the
acquisition process for a hybrid double-dwell system with antenna
diversity for DS-CDMA (direct sequence-code division multiple
access) using an adaptive threshold. Acquisition systems with a fixed
threshold value are unable to adapt to fast varying mobile
communications environments and may result in a high false alarm
rate, and/or low detection probability. Therefore, we propose an
adaptively varying threshold scheme through the use of a cellaveraging
constant false alarm rate (CA-CFAR) algorithm, which is
well known in the field of radar detection. We derive exact
expressions for the probabilities of detection and false alarm in
Rayleigh fading channels. The mean acquisition time of the system
under consideration is also derived. The performance of the system is
analyzed and compared to that of a hybrid single dwell system.
Abstract: Viscous heating becomes significant in the high speed
resin coating process of glass fibers for optical fiber manufacturing.
This study focuses on the coating resin flows inside the capillary
coating die of optical fiber coating applicator and they are numerically
simulated to examine the effects of viscous heating and subsequent
temperature increase in coating resin. Resin flows are driven by fast
moving glass fiber and the pressurization at the coating die inlet, while
the temperature dependent viscosity of liquid coating resin plays an
important role in the resin flow. It is found that the severe viscous
heating near the coating die wall profoundly alters the radial velocity
profiles and that the increase of final coating thickness by die
pressurization is amplified if viscous heating is present.
Abstract: Stable bacterial polymorphism on a single limiting resource may appear if between the evolved strains metabolic interactions take place that allow the exchange of essential nutrients [8]. Towards an attempt to predict the possible outcome of longrunning evolution experiments, a network based on the metabolic capabilities of homogeneous populations of every single gene knockout strain (nodes) of the bacterium E. coli is reconstructed. Potential metabolic interactions (edges) are allowed only between strains of different metabolic capabilities. Bacterial communities are determined by finding cliques in this network. Growth of the emerged hypothetical bacterial communities is simulated by extending the metabolic flux balance analysis model of Varma et al [2] to embody heterogeneous cell population growth in a mutual environment. Results from aerobic growth on 10 different carbon sources are presented. The upper bounds of the diversity that can emerge from single-cloned populations of E. coli such as the number of strains that appears to metabolically differ from most strains (highly connected nodes), the maximum clique size as well as the number of all the possible communities are determined. Certain single gene deletions are identified to consistently participate in our hypothetical bacterial communities under most environmental conditions implying a pattern of growth-condition- invariant strains with similar metabolic effects. Moreover, evaluation of all the hypothetical bacterial communities under growth on pyruvate reveals heterogeneous populations that can exhibit superior growth performance when compared to the performance of the homogeneous wild-type population.
Abstract: In Croatia, the majority of cultured marine fish species are reared in net cages. The intensive production of the fish in net cages may generate the considerable amount of bio waste and change water quality especially in enclosed and semi-enclosed coastal areas. The aim of this paper is to assess the potential impact of sea bass (Dicentrarchus labrax L.) cage farm on water quality. The weak relationship between food supply and water quality parameters (nutrient content and phytoplankton biomass) was found, but significant changes in oxygen saturation was observed in the cages during the warmer period of a year especially in the morning (occasionally it dropped below 70 %). Despite of, satisfactory results of water quality parameters, it is necessary to establish comprehensive monitoring process, especially to include quality assessment of fouling communities.
Abstract: This paper describes the design concepts and
implementation of a 5-Joint mechanical arm for a rescue robot named
CEO Mission II. The multi-joint arm is a five degree of freedom
mechanical arm with a four bar linkage, which can be stretched to
125 cm. long. It is controlled by a teleoperator via the user-friendly
control and monitoring GUI program. With Inverse Kinematics
principle, we developed the method to control the servo angles of all
arm joints to get the desired tip position. By clicking the determined
tip position or dragging the tip of the mechanical arm on the
computer screen to the desired target point, the robot will compute
and move its multi-joint arm to the pose as seen on the GUI screen.
The angles of each joint are calculated and sent to all joint servos
simultaneously in order to move the mechanical arm to the desired
pose at once. The operator can also use a joystick to control the
movement of this mechanical arm and the locomotion of the robot.
Many sensors are installed at the tip of this mechanical arm for
surveillance from the high level and getting the vital signs of victims
easier and faster in the urban search and rescue tasks. It works very
effectively and easy to control. This mechanical arm and its software
were developed as a part of the CEO Mission II Rescue Robot that
won the First Runner Up award and the Best Technique award from
the Thailand Rescue Robot Championship 2006. It is a low cost,
simple, but functioning 5-Jiont mechanical arm which is built from
scratch, and controlled via wireless LAN 802.11b/g. This 5-Jiont
mechanical arm hardware concept and its software can also be used
as the basic mechatronics to many real applications.
Abstract: this paper presents a novel scheme which is capable of reducing the error rate and improves the transmission performance in the asynchronous cooperative MIMO systems. A case study of image transmission is applied to prove the efficient of scheme. The linear dispersion structure is employed to accommodate the cooperative wireless communication network in the dynamic topology of structure, as well as to achieve higher throughput than conventional space–time codes based on orthogonal designs. The LDPC encoder without girth-4 and the STBC encoder with guard intervals are respectively introduced. The experiment results show that the combined coder of LDPC-STBC with guard intervals can be the good error correcting coders and BER performance in the asynchronous cooperative communication. In the case study of image transmission, the results show that in the transmission process, the image quality which is obtained by applied combined scheme is much better than it which is not applied the scheme in the asynchronous cooperative MIMO systems.
Abstract: In this paper a novel, simple and reliable digital firing
scheme has been implemented for speed control of three-phase
induction motor using ac voltage controller. The system consists of
three-phase supply connected to the three-phase induction motor via
three triacs and its control circuit. The ac voltage controller has three
modes of operation depending on the shape of supply current. The
performance of the induction motor differs in each mode where the
speed is directly proportional with firing angle in two modes and
inversely in the third one. So, the control system has to detect the
current mode of operation to choose the correct firing angle of triacs.
Three sensors are used to feed the line currents to control system to
detect the mode of operation. The control strategy is implemented
using a low cost Xilinx Spartan-3E field programmable gate array
(FPGA) device. Three PI-controllers are designed on FPGA to
control the system in the three-modes. Simulation of the system is
carried out using PSIM computer program. The simulation results
show stable operation for different loading conditions especially in
mode 2/3. The simulation results have been compared with the
experimental results from laboratory prototype.
Abstract: As a vital activity for companies, new product
development (NPD) is also a very risky process due to the high
uncertainty degree encountered at every development stage and the
inevitable dependence on how previous steps are successfully
accomplished. Hence, there is an apparent need to evaluate new
product initiatives systematically and make accurate decisions under
uncertainty. Another major concern is the time pressure to launch a
significant number of new products to preserve and increase the
competitive power of the company. In this work, we propose an
integrated decision-making framework based on neural networks and
fuzzy logic to make appropriate decisions and accelerate the
evaluation process. We are especially interested in the two initial
stages where new product ideas are selected (go/no go decision) and
the implementation order of the corresponding projects are
determined. We show that this two-staged intelligent approach allows
practitioners to roughly and quickly separate good and bad product
ideas by making use of previous experiences, and then, analyze a
more shortened list rigorously.
Abstract: Pyritisation halos are identified in weathering crusts and unconsolidated formations at five locations within large fault structure of the Urals’ eastern slope. Electron microscopy reveals the presence of inclusions and growths on pyrite faces – normally on cubic pyrite with striations, or combinations of cubes and other forms. Following neogenesis types are established: native elements and intermetallic compounds (including gold and silver), halogenides, sulphides, sulfosalts, tellurides, sulphotellurides,
selenides, tungstates, sulphates, phosphates, carbon-based substances. Direct relationship is noted between amount and diversity of such mineral phases, and proximity to and scale of ore-grade mineralization. Gold and silver, both in native form and within tellurides, presence of lead (galena, native lead), native tungsten, and, possibly, molybdenite and sulfosalts can indicate gold-bearing formations. First find of native tungsten in the Urals is for the first time – in crystallised and druse-like form. Link is suggested between unusual mineralization and “reducing” hydrothermal fluids from deep-seated faults at later stages of Urals’ reactivation.
Abstract: How to simulate experimentally the air flow and heat
transfer under microgravity on the ground is important, which has not
been completely solved so far. Influence of gravity on air natural
convection results in convection heat transfer on ground difference
from that on orbit. In order to obtain air temperature and velocity
deviations of manned spacecraft during terrestrial thermal test,
dimensionless number analysis and numerical simulation analysis are
performed. The calculated temperature distribution and velocity
distribution of the horizontal test cases are compared to the vertical
cases. The results show that the influence of gravity is neglected for
facility drawer racks and more obvious for vertical cabins.
Abstract: We integrate TiN/Ni/HfO2/Si RRAM cell with a
vertical gate-all-around (GAA) nanowire transistor to achieve
compact 4F2 footprint in a 1T1R configuration. The tip of the Si
nanowire (source of the transistor) serves as bottom electrode of the
memory cell. Fabricated devices with nanowire diameter ~ 50nm
demonstrate ultra-low current/power switching; unipolar switching
with 10μA/30μW SET and 20μA/30μW RESET and bipolar switching
with 20nA/85nW SET and 0.2nA/0.7nW RESET. Further, the
switching current is found to scale with nanowire diameter making the
architecture promising for future scaling.
Abstract: The significant effects of the interactions between the
system boundaries and the near wall molecules in miniaturized
gaseous devices lead to the formation of the Knudsen layer in which
the Navier-Stokes-Fourier (NSF) equations fail to predict the correct
associated phenomena. In this paper, the well-known lattice
Boltzmann method (LBM) is employed to simulate the fluid flow and
heat transfer processes in rarefied gaseous micro media. Persuaded
by the problematic deficiency of the LBM in capturing the Knudsen
layer phenomena, present study tends to concentrate on the effective
molecular mean free path concept the main essence of which is to
compensate the incapability of this mesoscopic method in dealing
with the momentum and energy transport within the above mentioned
kinetic boundary layer. The results show qualitative and quantitative
accuracy comparable to the solutions of the linearized Boltzmann
equation or the DSMC data for the Knudsen numbers of O (1) .
Abstract: Natural gas usually includes H2S component which is
very toxic, hazardous and corrosive to environment, human being and
process equipments, respectively. Therefore, sweetening of the gas
(separation of H2S) is inevitable. To achieve this purpose, using
packed-bed columns with liquid absorbents such as MEA or DEA is
very common. Due to some problems of usual packed columns
especially high pressure drop of gas phase, a novel kind of them
called wetted-wire column (WWC) has been invented. The column
decreases the pressure drop significantly and improves the absorption
efficiency. The packings are very thin rods (like wire) and as long as
column. The column has 100 wires with a triangular arrangement and
counter current flows of gas and liquid phases. The observation
showed that at the same conditions, the absorption performance was
quite comparable to conventional packed-bed towers and a very low
pressure drop.
Abstract: Designing and implementing intelligent systems has become a crucial factor for the innovation and development of better products of space technologies. A neural network is a parallel system, capable of resolving paradigms that linear computing cannot. Field programmable gate array (FPGA) is a digital device that owns reprogrammable properties and robust flexibility. For the neural network based instrument prototype in real time application, conventional specific VLSI neural chip design suffers the limitation in time and cost. With low precision artificial neural network design, FPGAs have higher speed and smaller size for real time application than the VLSI and DSP chips. So, many researchers have made great efforts on the realization of neural network (NN) using FPGA technique. In this paper, an introduction of ANN and FPGA technique are briefly shown. Also, Hardware Description Language (VHDL) code has been proposed to implement ANNs as well as to present simulation results with floating point arithmetic. Synthesis results for ANN controller are developed using Precision RTL. Proposed VHDL implementation creates a flexible, fast method and high degree of parallelism for implementing ANN. The implementation of multi-layer NN using lookup table LUT reduces the resource utilization for implementation and time for execution.
Abstract: This study investigated the relationship between urban
and rural ozone concentrations and quantified the extent to which
ambient rural conditions and the concentrations of other pollutants
can be used to predict urban ozone concentrations. The study
describes the variations of ozone in weekday and weekends as well as
the daily maximum recorded at selected monitoring stations. The
results showed that Putrajaya station had the highest concentrations
of O3 on weekend due the titration of NO during the weekday.
Additionally, Jerantut had the lowest average concentration with a
reading value high on Wednesdays. The comparisons of average and
maximum concentrations of ozone for the three stations showed that
the strongest significant correlation is recorded in Jerantut station
with the value R2= 0.769. Ozone concentrations originating from a
neighbouring urban site form a better predictor to the urban ozone
concentrations than widespread rural ozone at some levels of
temporal averaging. It is found that in urban and rural of Malaysian
peninsular, the concentration of ozone depends on the concentration
of NOx and seasonal meteorological factors. The HYSPLIT Model
(the northeast monsoon) showed that the wind direction can also
influence the concentration of ozone in the atmosphere in the studied
areas.
Abstract: Social Business Process Management (SBPM)
promises to overcome limitations of traditional BPM by allowing
flexible process design and enactment through the involvement of
users from a social community. This paper proposes a meta-model
and architecture for socially driven business process management
systems. It discusses the main facets of the architecture such as goalbased
role assignment that combines social recommendations with
user profile, and process recommendation, through a real example of
a charity organization.
Abstract: The electrical interaction between two axisymmetric
spheroidal particles in an electrolyte solution is examined numerically.
A Galerkin finite element method combined with a Newton-Raphson
iteration scheme is proposed to evaluate the spatial variation in the
electrical potential, and the result obtained used to estimate the
interaction energy between two particles. We show that if the surface
charge density is fixed, the potential gradient is larger at a point, which
has a larger curvature, and if surface potential is fixed, surface charge
density is proportional to the curvature. Also, if the total interaction
energy against closest surface-to-surface curve exhibits a primary
maximum, the maximum follows the order (oblate-oblate) >
(sphere-sphere)>(oblate-prolate)>(prolate-prolate), and if the curve
has a secondary minimum, the absolute value of the minimum follows
the same order.
Abstract: The following study aims to outline, whether the
perceptions of entrepreneurs about their entrepreneurial activities and
the underlying meanings of their activities are universal or whether
they vary systematically across cultures. In contrast to previous
studies, the phenomenographical approach and the resulting findings
of this study provide new insights into what constitutes
entrepreneurship by drawing an inference from the perceptions of
entrepreneurs in the United States and in Germany. Culture is shown
to have an important impact on entrepreneurship, since the
underlying meanings of entrepreneurship vary significantly among
the two sample groups. Furthermore, the study sheds more light on
the culturally contingent 'why' of entrepreneurship by looking at the
internal motivations of individuals instead of exclusively focusing on
character traits or external influences of the respective economic
environments.
Abstract: This study uses simulated meta-analysis to assess the effects of publication bias on meta-analysis estimates and to evaluate the efficacy of the trim and fill method in adjusting for these biases. The estimated effect sizes and the standard error were evaluated in terms of the statistical bias and the coverage probability. The results demonstrate that if publication bias is not adjusted it could lead to up to 40% bias in the treatment effect estimates. Utilization of the trim and fill method could reduce the bias in the overall estimate by more than half. The method is optimum in presence of moderate underlying bias but has minimal effects in presence of low and severe publication bias. Additionally, the trim and fill method improves the coverage probability by more than half when subjected to the same level of publication bias as those of the unadjusted data. The method however tends to produce false positive results and will incorrectly adjust the data for publication bias up to 45 % of the time. Nonetheless, the bias introduced into the estimates due to this adjustment is minimal
Abstract: The purpose of the study was to find out the efficacy
of selected mobility exercises and participation in special games on psychomotor abilities, functional abilities and skill performance
among intellectually disabled children of age group under 14. Thirty male students who were studying in Balar Kalvi Nilayam and YMCA
College Special School, Chennai, acted as subjects for the study.
They were only mild and moderate in intellectual disability. These
students did not undergo any special training or coaching programme apart from their regular routine physical activity classes as a part of
the curriculum in the school. They were attached at random, based on
age in which 30 belonged to under 14 age group, which was divided
into three equal group of ten for each experimental treatment. 10
students (Treatment group I) underwent calisthenics and special
games participation, 10 students (Treatment group II) underwent
aquatics and special games participation, 10 students (Treatment
group III) underwent yoga and special games participation. The subjects were tested on selected criterion variables prior (pre test)
and after twelve weeks of training (post test). The pre and post test
data collected from three groups on functional abilities(self care,
learning, capacity for independent living), psychomotor
variables(static balance, eye hand coordination, simple reaction time
test) and skill performance (bocce skill, badminton skill, table tennis
skill) were statistically examined for significant difference, by
applying the analysis ANACOVA. Whenever an 'F' ratio for
adjusted test was found to be significant for adjusted post test means,
Scheffe-s test was followed as a post-hoc test to determine which of
the paired mean differences was significant. The result of the study
showed that among under 14 age groups there was a significant improvement on selected criterion variables such as, Balance,
Coordination, self-care and learning and also in Bocce, Badminton & Table Tennis skill performance, due to mobility exercises and
participation in special games. However there were no significant
differences among the groups.