Abstract: A new dynamic clustering approach (DCPSO), based
on Particle Swarm Optimization, is proposed. This approach is
applied to unsupervised image classification. The proposed approach
automatically determines the "optimum" number of clusters and
simultaneously clusters the data set with minimal user interference.
The algorithm starts by partitioning the data set into a relatively large
number of clusters to reduce the effects of initial conditions. Using
binary particle swarm optimization the "best" number of clusters is
selected. The centers of the chosen clusters is then refined via the Kmeans
clustering algorithm. The experiments conducted show that
the proposed approach generally found the "optimum" number of
clusters on the tested images.
Abstract: Learning is the acquisition of new mental schemata, knowledge, abilities and skills which can be used to solve problems potentially more successfully. The learning process is optimum when it is assisted and personalized. Learning is not a single activity, but should involve many possible activities to make learning become meaningful. Many e-learning applications provide facilities to support teaching and learning activities. One way to identify whether the e-learning system is being used by the learners is through the number of hits that can be obtained from the e-learning system's log data. However, we cannot rely solely to the number of hits in order to determine whether learning had occurred meaningfully. This is due to the fact that meaningful learning should engage five characteristics namely active, constructive, intentional, authentic and cooperative. This paper aims to analyze the e-learning activities that is meaningful to learning. By focusing on the meaningful learning characteristics, we match it to the corresponding Moodle e-learning activities. This analysis discovers the activities that have high impact to meaningful learning, as well as activities that are less meaningful. The high impact activities is given high weights since it become important to meaningful learning, while the low impact has less weight and said to be supportive e-learning activities. The result of this analysis helps us categorize which e-learning activities that are meaningful to learning and guide us to measure the effectiveness of e-learning usage.
Abstract: A stack with a small critical temperature gradient is
desirable for a standing wave thermoacoustic engine to obtain a low
onset temperature difference (the minimum temperature difference to
start engine-s self-oscillation). The viscous and heat relaxation loss in
the stack determines the critical temperature gradient. In this work, a
dimensionless critical temperature gradient factor is obtained based
on the linear thermoacoustic theory. It is indicated that the
impedance determines the proportion between the viscous loss, heat
relaxation losses and the power production from the heat energy. It
reveals the effects of the channel dimensions, geometrical
configuration and the local acoustic impedance on the critical
temperature gradient in stacks. The numerical analysis shows that
there exists a possible optimum combination of these parameters
which leads to the lowest critical temperature gradient. Furthermore,
several different geometries have been tested and compared
numerically.
Abstract: Fuller’s earth is a fine-grained, naturally occurring substance that has a substantial ability to adsorb impurities. In the present study Fuller’s earth has been characterized and used for the removal of Pb(II) from aqueous solution. The effect of various physicochemical parameters such as pH, adsorbent dosage and shaking time on adsorption were studied. The result of the equilibrium studies showed that the solution pH was the key factor affecting the adsorption. The optimum pH for adsorption was 5. Kinetics data for the adsorption of Pb(II) was best described by pseudo-second order model. The effective diffusion co-efficient for Pb(II) adsorption was of the order of 10-8 m2/s. The adsorption data for metal adsorption can be well described by Langmuir adsorption isotherm. The maximum uptake of metal was 103.3 mg/g of adsorbent. Mass transfer analysis was also carried out for the adsorption process. The values of mass transfer coefficients obtained from the study indicate that the velocity of the adsorbate transport from bulk to the solid phase was quite fast. The mean sorption energy calculated from Dubinin-Radushkevich isotherm indicated that the metal adsorption process was chemical in nature.
Abstract: Optimal design of structure has a main role in reduction of material usage which leads to deduction in the final cost of construction projects. Evolutionary approaches are found to be more successful techniques for solving size and shape structural optimization problem since it uses a stochastic random search instead of a gradient search. By reviewing the recent literature works the problem found was the optimization of weight. A new meta-heuristic algorithm called as Cuckoo Search (CS) Algorithm has used for the optimization of the total weight of the truss structures. This paper has used set of 10 bars and 25 bars trusses for the testing purpose. The main objective of this work is to reduce the number of iterations, weight and the total time consumption. In order to demonstrate the effectiveness of the present method, minimum weight design of truss structures is performed and the results of the CS are compared with other algorithms.
Abstract: In this paper, the optimum weight and cost of a laminated composite plate is seeked, while it undergoes the heaviest load prior to a complete failure. Various failure criteria are defined for such structures in the literature. In this work, the Tsai-Hill theory is used as the failure criterion. The theory of analysis was based on the Classical Lamination Theory (CLT). A newly type of Genetic Algorithm (GA) as an optimization technique with a direct use of real variables was employed. Yet, since the optimization via GAs is a long process, and the major time is consumed through the analysis, Radial Basis Function Neural Networks (RBFNN) was employed in predicting the output from the analysis. Thus, the process of optimization will be carried out through a hybrid neuro-GA environment, and the procedure will be carried out until a predicted optimum solution is achieved.
Abstract: Extraction of laccase produced by L. polychrous in an
aqueous two-phase system, composed of polyethylene glycol and
phosphate salt at pH 7.0 and 250C was investigated. The effect of
PEG molecular weight, PEG concentration and phosphate
concentration was determined. Laccase preferentially partitioned to
the top phase. Good extraction of laccase to the top phase was
observed with PEG 4000. The optimum system was found in the
system containing 12% w/w PEG 4000 and 16% w/w phosphate salt
with KE of 88.3, purification factor of 3.0-fold and 99.1% yield.
Some properties of the enzyme such as thermal stability, effect of
heavy metal ions and kinetic constants were also presented in this
work. The thermal stability decreased sharply with high temperature
above 60 0C. The enzyme was inhibited by Cd2+, Pb2+, Zn2+ and
Cu2+. The Vmax and Km values of the enzyme were 74.70
μmol/min/ml and 9.066 mM respectively.
Abstract: wind catchers have been served as a cooling system, used to provide acceptable ventilation by means of renewable energy of wind. In the present study, the city of Yazd in arid climate is selected as case study. From the architecture point of view, learning about wind catchers in this study is done by means of field surveys. Research method for selection of the case is based on random form, and analytical method. Wind catcher typology and knowledge of relationship governing the wind catcher's architecture were those measures that are taken for the first time. 53 wind catchers were analyzed. The typology of the wind-catchers is done by the physical analyzing, patterns and common concepts as incorporated in them. How the architecture of wind catcher can influence their operations by analyzing thermal behavior are the archetypes of selected wind catchers. Calculating fluids dynamics science, fluent software and numerical analysis are used in this study as the most accurate analytical approach. The results obtained from these analyses show the formal specifications of wind catchers with optimum operation in Yazd. The knowledge obtained from the optimum model could be used for design and construction of wind catchers with more improved operation
Abstract: DG application has received increasing attention during
recent years. The impact of DG on various aspects of distribution system
operation, such as reliability and energy loss, depend highly on DG
location in distribution feeder. Optimal DG placement is an important
subject which has not been fully discussed yet.
This paper presents an optimization method to determine optimal DG
placement, based on a cost/worth analysis approach. This method
considers technical and economical factors such as energy loss, load point
reliability indices and DG costs, and particularly, portability of DG. The
proposed method is applied to a test system and the impacts of different
parameters such as load growth rate and load forecast uncertainty (LFU)
on optimum DG location are studied.
Abstract: LSP routing is among the prominent issues in MPLS
networks traffic engineering. The objective of this routing is to
increase number of the accepted requests while guaranteeing the
quality of service (QoS). Requested bandwidth is the most important
QoS criterion that is considered in literatures, and a various number
of heuristic algorithms have been presented with that regards. Many
of these algorithms prevent flows through bottlenecks of the network
in order to perform load balancing, which impedes optimum
operation of the network. Here, a modern routing algorithm is
proposed as MIRAD: having a little information of the network
topology, links residual bandwidth, and any knowledge of the
prospective requests it provides every request with a maximum
bandwidth as well as minimum end-to-end delay via uniform load
distribution across the network. Simulation results of the proposed
algorithm show a better efficiency in comparison with similar
algorithms.
Abstract: In this paper, an attempt is made to compute the total
optimal cost of interdependent queuing system with controllable
arrival rates as an important performance measure of the system. An
example of application has also been presented to exhibit the use of
the model. Finally, numerical demonstration based on a computing
algorithm and variational effects of the model with the help of the
graph have also been presented.
Abstract: In this paper, Optimum adaptive loading algorithms
are applied to multicarrier system with Space-Time Block Coding
(STBC) scheme associated with space-time processing based on
singular-value decomposition (SVD) of the channel matrix over
Rayleigh fading channels. SVD method has been employed in
MIMO-OFDM system in order to overcome subchannel interference.
Chaw-s and Compello-s algorithms have been implemented to obtain
a bit and power allocation for each subcarrier assuming instantaneous
channel knowledge. The adaptive loaded SVD-STBC scheme is
capable of providing both full-rate and full-diversity for any number
of transmit antennas. The effectiveness of these techniques has
demonstrated through the simulation of an Adaptive loaded SVDSTBC
system, and the comparison shown that the proposed
algorithms ensure better performance in the case of MIMO.
Abstract: This paper studies the application of a variety of
sawdust materials in the production of lightweight insulating bricks.
First, the mineralogical and chemical composition of clays was determined. Next, ceramic bricks were fabricated with different
quantities of materials (3–6 and 9 wt. % for sawdust, 65 wt. % for grey clay, 24–27 and 30 wt. % for yellow clay and 2 wt% of tuff).
These bricks were fired at 800 and 950 °C. The effect of adding this sawdust on the technological behaviour of the brick was assessed by
drying and firing shrinkage, water absorption, porosity, bulk density
and compressive strength. The results have shown that the optimum
sintering temperature is 950 °C. Below this temperature, at 950 °C,
increased open porosity was observed, which decreased the compressive strength of the bricks. Based on the results obtained, the
optimum amounts of waste were 9 wt. % sawdust of eucalyptus, 24 wt. % shaping moisture and 1.6 particle size diameter. These percentages produced bricks whose mechanical properties were
suitable for use as secondary raw materials in ceramic brick
production.
Abstract: In the micro and nano-technology industry, the
«clean-rooms» dedicated to manufacturing chip, are equipped with
the most sophisticated equipment-tools. There use a large number of
resources in according to strict specifications for an optimum
working and result. The distribution of «utilities» to the production is
assured by teams who use a supervision tool.
The studies show the interest to control the various parameters of
production or/and distribution, in real time, through a reliable and
effective supervision tool. This document looks at a large part of the
functions that the supervisor must assure, with complementary
functionalities to help the diagnosis and simulation that prove very
useful in our case where the supervised installations are complexed
and in constant evolution.
Abstract: The aim of the present study was to evaluate the
mucoadhesion and the release of nicotinamide gel formulations using
in vitro methods. An agar plate technique was used to investigate the
adhesiveness of the gels whereas a diffusion apparatus was employed
to determine the release of nicotinamide from the gels. In this
respect, 10% w/w nicotinamide gels containing bioadhesive
polymers: Carbopol 934P (0.5-2% w/w), hydroxypropylmethyl
cellulose (HPMC) (4-10% w/w), sodium carboxymethyl cellulose
(SCMC) (4-6% w/w) and methylcellulose 4000 (MC) (3-5% w/w)
were prepared. The gel formulations had pH values in the range of
7.14 - 8.17, which were considered appropriate to oral mucosa
application. In general, the rank order of pH values appeared to be
SCMC > MC4000 > HPMC > Carbopol 934P. Types and
concentrations of polymers used somewhat affected the
adhesiveness. It was found that anionic polymers (Carbopol 934 and
SCMC) adhered more firmly to the agar plate than the neutral
polymers (HPMC and MC 4000). The formulation containing 0.5%
Carbopol 934P (F1) showed the highest release rate. With the
exception of the formulation F1, the neutral polymers tended to give
higher relate rates than the anionic polymers. For oral tissue
treatment, the optimum has to be balanced between the residence
time (adhesiveness) of the formulations and the release rate of the
drug. The formulations containing the anionic polymers: Carbopol
934P or SCMC possessed suitable physical properties (appearance,
pH and viscosity). In addition, for anionic polymer formulations,
justifiable mucoadhesive properties and reasonable release rates of
nicotinamide were achieved. Accordingly, these gel formulations
may be applied for the treatment of oral mucosal lesions.
Abstract: In this paper, we are going to determine the threshold levels of adaptive modulation in a burst by burst CDMA system by a suboptimum method so that the above method attempts to increase the average bit per symbol (BPS) rate of transceiver system by switching between the different modulation modes in variable channel condition. In this method, we choose the minimum values of average bit error rate (BER) and maximum values of average BPS on different values of average channel signal to noise ratio (SNR) and then calculate the relative threshold levels of them, so that when the instantaneous SNR increases, a higher order modulation be employed for increasing throughput and vise-versa when the instantaneous SNR decreases, a lower order modulation be employed for improvement of BER. In transmission step, by this adaptive modulation method, in according to comparison between obtained estimation of pilot symbols and a set of above suboptimum threshold levels, above system chooses one of states no transmission, BPSK, 4QAM and square 16QAM for modulation of data. The expected channel in this paper is a slow Rayleigh fading.
Abstract: The control of oxygen flow rate during growth of
titanium dioxide by mass flow controller in DC plasma sputtering
growth system is studied. The impedance of TiO2 films for inductance
effect is influenced by annealing time and oxygen flow rate. As
annealing time is increased, the inductance of TiO2 film is the more.
The growth condition of optimum and maximum inductance for TiO2
film to serve as sensing device are oxygen flow rate of 15 sccm and
large annealing time. The large inductance of TiO2 film will be
adopted to fabricate the biosensor to obtain the high sensitivity of
sensing in biology.
Abstract: The antioxidant compounds are needed for the food, beverages, and pharmaceuticals industry. For this purpose, an appropriate method is required to measure the antioxidant properties in various types of samples. Spectrophotometric method usually used has some weaknesses, including the high price, long sample preparation time, and less sensitivity. Among the alternative methods developed to overcome these weaknesses is antioxidant biosensor based on superoxide dismutase (SOD) enzyme. Therefore, this study was carried out to measure the SOD activity originating from Deinococcus radiodurans and to determine its kinetics properties. Carbon paste electrode modified with ferrocene and immobilized SOD exhibited anode and cathode current peak at potential of +400 and +300mv respectively, in both pure SOD and SOD of D. radiodurans. This indicated that the current generated was from superoxide catalytic dismutation reaction by SOD. Optimum conditions for SOD activity was at pH 9 and temperature of 27.50C for D. radiodurans SOD, and pH 11 and temperature of 200C for pure SOD. Dismutation reaction kinetics of superoxide catalyzed by SOD followed the Lineweaver-Burk kinetics with D. radiodurans SOD KMapp value was smaller than pure SOD. The result showed that D. radiodurans SOD had higher enzyme-substrate affinity and specificity than pure SOD. It concluded that D. radiodurans SOD had a great potential as biological recognition component for antioxidant biosensor.
Abstract: In the process of polyethylene extrusion polymer
material similar to powder or granule is under compression, melting
and transmission operation and on base of special form, extrudate has
been produced. Twin-screw extruders are applicable in industries
because of their high capacity. The powder mixing with chemical
additives and melting with thermal and mechanical energy in three
zones (feed, compression and metering zone) and because of gear
pump and screw's pressure, converting to final product in latest plate.
Extruders with twin-screw and short distance between screws are
better than other types because of their high capacity and good
thermal and mechanical stress.
In this paper, process of polyethylene extrusion and various tapes
of extruders are studied. It is necessary to have an exact control on
process to producing high quality products with safe operation and
optimum energy consumption.
The granule size is depending on granulator motor speed. Results
show at constant feed rate a decrease in granule size was found whit
Increase in motor speed. Relationships between HDPE feed rate and
speed of granulator motor, main motor and gear pump are calculated
following as:
x = HDPE feed flow rate, yM = Main motor speed
yM = (-3.6076e-3) x^4+ (0.24597) x^3+ (-5.49003) x^2+ (64.22092)
x+61.66786 (1)
x = HDPE feed flow rate, yG = Gear pump speed
yG = (-2.4996e-3) x^4+ (0.18018) x^3+ (-4.22794) x^2+ (48.45536)
x+18.78880 (2)
x = HDPE feed flow rate, y = Granulator motor speed
10th Degree Polynomial Fit: y = a+bx+cx^2+dx^3... (3)
a = 1.2751, b = 282.4655, c = -165.2098,
d = 48.3106, e = -8.18715, f = 0.84997
g = -0.056094, h = 0.002358, i = -6.11816e-5
j = 8.919726e-7, k = -5.59050e-9
Abstract: This paper presents the results related to the
interference reduction technique in multistage multiuser detector for
asynchronous DS-CDMA system. To meet the real-time
requirements for asynchronous multiuser detection, a bit streaming,
cascade architecture is used. An asynchronous multiuser detection
involves block-based computations and matrix inversions. The paper
covers iterative-based suboptimal schemes that have been studied to
decrease the computational complexity, eliminate the need for matrix
inversions, decreases the execution time, reduces the memory
requirements and uses joint estimation and detection process that
gives better performance than the independent parameter estimation
method. The stages of the iteration use cascaded and bits processed
in a streaming fashion. The simulation has been carried out for
asynchronous DS-CDMA system by varying one parameter, i.e.,
number of users. The simulation result exhibits that system gives
optimum bit error rate (BER) at 3rd stage for 15-users.