Abstract: One of the main concerns about parallel mechanisms
is the presence of singular points within their workspaces. In singular
positions the mechanism gains or loses one or several degrees of
freedom. It is impossible to control the mechanism in singular
positions. Therefore, these positions have to be avoided. This is a
vital need especially in computer controlled machine tools designed
and manufactured on the basis of parallel mechanisms. This need has
to be taken into consideration when selecting design parameters. A
prerequisite to this is a thorough knowledge about the effect of
design parameters and constraints on singularity. In this paper,
quality condition index was introduced as a criterion for evaluating
singularities of different configurations of a hexapod mechanism
obtainable by different design parameters. It was illustrated that this
method can effectively be employed to obtain the optimum
configuration of hexapod mechanism with the aim of avoiding
singularity within the workspace. This method was then employed to
design the hexapod table of a CNC milling machine.
Abstract: Wireless sensor network is formed with the combination of sensor nodes and sink nodes. Recently Wireless sensor network has attracted attention of the research community. The main application of wireless sensor network is security from different attacks both for mass public and military. However securing these networks, by itself is a critical issue due to many constraints like limited energy, computational power and lower memory. Researchers working in this area have proposed a number of security techniques for this purpose. Still, more work needs to be done.In this paper we provide a detailed discussion on security in wireless sensor networks. This paper will help to identify different obstacles and requirements for security of wireless sensor networks as well as highlight weaknesses of existing techniques.
Abstract: In this study, the kinetics of osmotic dehydration of melons (Tille variety) in a ternary system followed by air-drying for preserving melons in the summer to be used in the winter were investigated. The effect of different osmotic solution concentrations 30, 40 and 50% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratios 1:4, 1:5 and 1:6 on the mass transfer kinetics during osmotic dehydration of melon in ternary solution namely sucrosesalt- water followed by air-drying were studied. The diffusivity of water during air-drying was enhanced after the fruit samples were immersed in the osmotic solution after 60 min. Samples non-treated and pre-treated during one hour in osmotic solutions with 60% (w/w) of sucrose with 10% NaCl salt and fruit to solution ratio of 1:4 were dried in a hot air-dryer at 60oC (2 m/s) until equilibrium was achieved.
Abstract: The capturing of gel electrophoresis image represents
the output of a DNA computing algorithm. Before this image is being
captured, DNA computing involves parallel overlap assembly (POA)
and polymerase chain reaction (PCR) that is the main of this
computing algorithm. However, the design of the DNA
oligonucleotides to represent a problem is quite complicated and is
prone to errors. In order to reduce these errors during the design stage
before the actual in-vitro experiment is carried out; a simulation
software capable of simulating the POA and PCR processes is
developed. This simulation software capability is unlimited where
problem of any size and complexity can be simulated, thus saving
cost due to possible errors during the design process. Information
regarding the DNA sequence during the computing process as well as
the computing output can be extracted at the same time using the
simulation software.
Abstract: Social resilience has role to govern the local community and coastal fisheries resources toward sustainable fisheries development in tsunami affected area. This paper asses, explore and investigates of indigenous institutions, external and internal facilitators toward strengthening social resilience. Identification of the genuine organizations role had been conducted twice by using Rapid Assessment Appraisal, Focus Group Discussion, and in-depth interview for collecting primary and secondary data. Local wisdom had a contribution and adaptable to rebound social resilience. The Panglima Laot Lhok (sea commander) had determined and adapted role on recovery of the fishing community, particularly facilitated aid delivery to fishermen, as shown in anchovy fisheries relief case in Krueng Raya Bay. Toke Bangku (financial trader) had stimulated for reinforcement of advance payment and market channel. The other institutions supported upon linking and bridging connectivity among stakeholders. Collaborative governance can avoid conflict, reduce donor dependency and strengthen social resilience within fishing community.
Abstract: In text categorization problem the most used method
for documents representation is based on words frequency vectors
called VSM (Vector Space Model). This representation is based only
on words from documents and in this case loses any “word context"
information found in the document. In this article we make a
comparison between the classical method of document representation
and a method called Suffix Tree Document Model (STDM) that is
based on representing documents in the Suffix Tree format. For the
STDM model we proposed a new approach for documents
representation and a new formula for computing the similarity
between two documents. Thus we propose to build the suffix tree
only for any two documents at a time. This approach is faster, it has
lower memory consumption and use entire document representation
without using methods for disposing nodes. Also for this method is
proposed a formula for computing the similarity between documents,
which improves substantially the clustering quality. This
representation method was validated using HAC - Hierarchical
Agglomerative Clustering. In this context we experiment also the
stemming influence in the document preprocessing step and highlight
the difference between similarity or dissimilarity measures to find
“closer" documents.
Abstract: The purpose of this study is to investigate the
efficiency of a double-layer roof in collecting solar energy as an
application to the areas such as raising high-end temperature of
organic Rankine cycle (ORC). The by-product of the solar roof is to
reduce building air-conditioning loads. The experimental apparatus
are arranged to evaluate the effects of the solar roof in absorbing solar
energy. The flow channel is basically formed by an aluminum plate on
top of a plywood plate. The geometric configurations in which the
effects of absorbing energy is analyzed include: a bare uncovered
aluminum plate, a glass-covered aluminum plate, a
glass-covered/black-painted aluminum plate, a plate with variable
lengths, a flow channel with stuffed material (in an attempt on
enhancement of heat conduction), and a flow channel with variable
slanted angles. The experimental results show that the efficiency of
energy collection varies from 0.6 % to 11 % for the geometric
configurations mentioned above. An additional study is carried out
using CFD simulation to investigate the effects of fins on the
aluminum plate. It shows that due to vastly enhanced heat conduction,
the efficiency can reach ~23 % if 50 fins are installed on the aluminum
plate. The study shows that a double-layer roof can efficiently absorb
solar energy and substantially reduce building air-conditioning
loads. On the high end of an organic Rankine cycle, a solar pond is
used to replace the warm surface water of the sea as OTEC (ocean
thermal energy conversion) is the driving energy for the ORC. The
energy collected from the double-layered solar roof can be pumped
into the pond and raise the pond temperature as the pond surface area is
equivalently increased by nearly one-fourth of the total area of the
double-layer solar roof. The effect of raising solar pond temperature is
especially prominent if the double-layer solar roofs are installed in a
community area.
Abstract: The fast growing accessibility and capability of emerging technologies have fashioned enormous possibilities of designing, developing and implementing innovative teaching methods in the classroom. The global technological scenario has paved the way to new pedagogies in teaching-learning process focusing on technology based learning environment and its impact on student achievement. The present experimental study was conducted to determine the effectiveness of technology based learning environment on student achievement in English as a foreign language. The sample of the study was 90 students of 10th grade of a public school located in Islamabad. A pretest- posttest equivalent group design was used to compare the achievement of the two groups. A Pretest and A posttest containing 50 items each from English textbook were developed and administered. The collected data were statistically analyzed. The results showed that there was a significant difference between the mean scores of Experimental group and the Control group. The performance of Experimental group was better on posttest scores that indicted that teaching through technology based learning environment enhanced the achievement level of the students. On the basis of the results, it was recommended that teaching and learning through information and communication technologies may be adopted to enhance the language learning capability of the students.
Abstract: In this paper we consider a nonlinear feedback control
called augmented automatic choosing control (AACC) using the
gradient optimization automatic choosing functions for nonlinear
systems. Constant terms which arise from sectionwise linearization
of a given nonlinear system are treated as coefficients of a stable
zero dynamics. Parameters included in the control are suboptimally
selected by expanding a stable region in the sense of Lyapunov
with the aid of the genetic algorithm. This approach is applied to
a field excitation control problem of power system to demonstrate
the splendidness of the AACC. Simulation results show that the new
controller can improve performance remarkably well.
Abstract: Study was conducted to determine the concentration of
copper, cadmium, lead and zinc in Cabomba furcata that found
abundance in Lake Chini. This aquatic plant was collected randomly
within the lake for heavy metal determination. Water quality
measurement was undertaken in situ for temperature, pH,
conductivity and dissolved oksigen using portable multi sensor probe
YSI model 556. The C. furcata was digested using wet digestion
method and heavy metal concentrations were analysed using Atomic
Absorption Spectrometer (AAS) Perkin Elmer 4100B (flame
method). Result of water quality classify Lake Chini between class II
to class III using Malaysian Water Quality Standard. According to
this standard, Lake Chini has moderate quality, which normal for
natural lake. Heavy metal concentrations in C.furcata were low and
found to be lower than the critical toxic value in aquatic plants. Oneway
ANOVA test indicated the heavy metal concentrations in
C.furcata were significantly differ between sampling location. Water
quality and heavy metal concentrations indicates that Lake Chini was
not receives anthropogenic load from nearby activities.
Abstract: Because of excellent properties, people has paid more
attention to SPIHI algorithm, which is based on the traditional wavelet
transformation theory, but it also has its shortcomings. Combined the
progress in the present wavelet domain and the human's visual
characteristics, we propose an improved algorithm based on human
visual characteristics of SPIHT in the base of analysis of SPIHI
algorithm. The experiment indicated that the coding speed and quality
has been enhanced well compared to the original SPIHT algorithm,
moreover improved the quality of the transmission cut off.
Abstract: Drilling is the most common machining operation and it forms the highest machining cost in many manufacturing activities including automotive engine production. The outcome of this operation depends upon many factors including utilization of proper cutting tool geometry, cutting tool material and the type of coating used to improve hardness and resistance to wear, and also cutting parameters. With the availability of a large array of tool geometries, materials and coatings, is has become a challenging task to select the best tool and cutting parameters that would result in the lowest machining cost or highest profit rate. This paper describes an algorithm developed to help achieve good performances in drilling operations by automatically determination of proper cutting tools and cutting parameters. It also helps determine machining sequences resulting in minimum tool changes that would eventually reduce machining time and cost where multiple tools are used.
Abstract: This paper describes an effective solution to the task
of a remote monitoring of super-extended objects (oil and gas
pipeline, railways, national frontier). The suggested solution is based
on the principle of simultaneously monitoring of seismoacoustic and
optical/infrared physical fields. The principle of simultaneous
monitoring of those fields is not new but in contrast to the known
solutions the suggested approach allows to control super-extended
objects with very limited operational costs. So-called C-OTDR
(Coherent Optical Time Domain Reflectometer) systems are used to
monitor the seismoacoustic field. Far-CCTV systems are used to
monitor the optical/infrared field. A simultaneous data processing
provided by both systems allows effectively detecting and classifying
target activities, which appear in the monitored objects vicinity. The
results of practical usage had shown high effectiveness of the
suggested approach.
Abstract: In this paper the performance of unified power flow
controller is investigated in controlling the flow of po wer over the
transmission line. Voltage sources model is utilized to study the
behaviour of the UPFC in regulating the active, reactive power and
voltage profile. This model is incorporated in Newton Raphson
algorithm for load flow studies. Simultaneous method is employed
in which equations of UPFC and the power balance equations of
network are combined in to one set of non-linear algebraic equations.
It is solved according to the Newton raphson algorithm. Case studies
are carried on standard 5 bus network. Simulation is done in Matlab.
The result of network with and without using UPFC are compared in
terms of active and reactive power flows in the line and active and
reactive power flows at the bus to analyze the performance of UPFC.
Abstract: An edge based local search algorithm, called ELS, is proposed for the maximum clique problem (MCP), a well-known combinatorial optimization problem. ELS is a two phased local search method effectively £nds the near optimal solutions for the MCP. A parameter ’support’ of vertices de£ned in the ELS greatly reduces the more number of random selections among vertices and also the number of iterations and running times. Computational results on BHOSLIB and DIMACS benchmark graphs indicate that ELS is capable of achieving state-of-the-art-performance for the maximum clique with reasonable average running times.
Abstract: This paper presents a novel CMOS four-transistor
SRAM cell for very high density and low power embedded SRAM
applications as well as for stand-alone SRAM applications. This cell
retains its data with leakage current and positive feedback without
refresh cycle. The new cell size is 20% smaller than a conventional
six-transistor cell using same design rules. Also proposed cell uses
two word-lines and one pair bit-line. Read operation perform from
one side of cell, and write operation perform from another side of
cell, and swing voltage reduced on word-lines thus dynamic power
during read/write operation reduced. The fabrication process is fully
compatible with high-performance CMOS logic technologies,
because there is no need to integrate a poly-Si resistor or a TFT load.
HSPICE simulation in standard 0.25μm CMOS technology confirms
all results obtained from this paper.
Abstract: Optimal load shedding (LS) design as an emergency plan is one of the main control challenges posed by emerging new uncertainties and numerous distributed generators including renewable energy sources in a modern power system. This paper presents an overview of the key issues and new challenges on optimal LS synthesis concerning the integration of wind turbine units into the power systems. Following a brief survey on the existing LS methods, the impact of power fluctuation produced by wind powers on system frequency and voltage performance is presented. The most LS schemas proposed so far used voltage or frequency parameter via under-frequency or under-voltage LS schemes. Here, the necessity of considering both voltage and frequency indices to achieve a more effective and comprehensive LS strategy is emphasized. Then it is clarified that this problem will be more dominated in the presence of wind turbines.
Abstract: The fine structure of supercavitation in the wake of a
symmetrical cylinder is studied with high-speed video cameras. The
flow is observed in a cavitation tunnel at the speed of 8m/sec when the
sidewall and the wake are partially filled with the massive cavitation
bubbles. The present experiment observed that a two-dimensional
ripple wave with a wave length of 0.3mm is propagated in a
downstream direction, and then abruptly increases to a thicker
three-dimensional layer. IR-photography recorded that the wakes
originated from the horseshoe vortexes alongside the cylinder. The
wake was developed to inside the dead water zone, which absorbed the
bubbly wake propelled from the separated vortices at the center of the
cylinder. A remote sensing classification technique (maximum most
likelihood) determined that the surface porosity was 0.2, and the mean
speed in the mixed wake was 7m/sec. To confirm the existence of
two-dimensional wave motions in the interface, the experiments were
conducted at a very low frequency, and showed similar gravity waves
in both the upper and lower interfaces.
Abstract: This paper presents a finite point method based on
directional derivatives for diffusion equation on 2D scattered points.
To discretize the diffusion operator at a given point, a six-point stencil
is derived by employing explicit numerical formulae of directional
derivatives, namely, for the point under consideration, only five
neighbor points are involved, the number of which is the smallest for
discretizing diffusion operator with first-order accuracy. A method for
selecting neighbor point set is proposed, which satisfies the solvability
condition of numerical derivatives. Some numerical examples are
performed to show the good performance of the proposed method.
Abstract: A new code for spectral-amplitude coding optical
code-division multiple-access system is proposed called Random
diagonal (RD) code. This code is constructed using code segment and
data segment. One of the important properties of this code is that the
cross correlation at data segment is always zero, which means that
Phase Intensity Induced Noise (PIIN) is reduced. For the performance
analysis, the effects of phase-induced intensity noise, shot noise, and
thermal noise are considered simultaneously. Bit-error rate (BER)
performance is compared with Hadamard and Modified Frequency
Hopping (MFH) codes. It is shown that the system using this new
code matrices not only suppress PIIN, but also allows larger number
of active users compare with other codes. Simulation results shown
that using point to point transmission with three encoded channels,
RD code has better BER performance than other codes, also its found
that at 0 dbm PIIN noise are 10-10 and 10-11 for RD and MFH
respectively.