Abstract: Quasigroups are algebraic structures closely related to
Latin squares which have many different applications. The
construction of block cipher is based on quasigroup string
transformation. This article describes a block cipher based
Quasigroup of order 256, suitable for fast software encryption of
messages written down in universal ASCII code. The novelty of this
cipher lies on the fact that every time the cipher is invoked a new set
of two randomly generated quasigroups are used which in turn is
used to create a pair of quasigroup of dual operations. The
cryptographic strength of the block cipher is examined by calculation
of the xor-distribution tables. In this approach some algebraic
operations allows quasigroups of huge order to be used without any
requisite to be stored.
Abstract: This paper describes an experience of research,
development and innovation applied in Industrial Naval at (Science
and Technology Corporation for the Development of Shipbuilding
Industry, Naval in Colombia (COTECMAR) particularly through
processes of research, innovation and technological development,
based on theoretical models related to organizational knowledge
management, technology management and management of human
talent and integration of technology platforms. It seeks ways to
facilitate the initial establishment of environments rich in
information, knowledge and content-supported collaborative
strategies on dynamic processes missionary, seeking further
development in the context of research, development and innovation
of the Naval Engineering in Colombia, making it a distinct basis for
the generation of knowledge assets from COTECMAR.
The integration of information and communication technologies,
supported on emerging technologies (mobile technologies, wireless,
digital content via PDA, and content delivery services on the Web 2.0
and Web 3.0) as a view of the strategic thrusts in any organization
facilitates the redefinition of processes for managing information and
knowledge, enabling the redesign of workflows, the adaptation of
new forms of organization - preferably in networking and support the
creation of symbolic-inside-knowledge promotes the development of
new skills, knowledge and attitudes of the knowledge worker
Abstract: Auckland has a temperate climate with comfortable
warm, dry summers and mild, wet winters. An Auckland school
normally does not need air conditioning for cooling during the
summer and only need heating during the winter. The space hating
energy is the major portion of winter school energy consumption and
the winter energy consumption is major portion of annual school
energy consumption. School building thermal design should focus
on the winter thermal performance for reducing the space heating
energy. A number of Auckland schools- design data and energy
consumption data are used for this study. This pilot study
investigates the relationships between their energy consumption data
and school building design data to improve future school design for
energy efficiency.
Abstract: Manufacturing components of fiber-reinforced
thermoplastics requires three steps: heating the matrix, forming and
consolidation of the composite and terminal cooling the matrix. For
the heating process a pre-determined temperature distribution through
the layers and the thickness of the pre-consolidated sheets is
recommended to enable forming mechanism. Thus, a design for the
heating process for forming composites with thermoplastic matrices
is necessary. To obtain a constant temperature through thickness and
width of the sheet, the heating process was analyzed by the help of
the finite element method. The simulation models were validated by
experiments with resistance thermometers as well as with an infrared
camera. Based on the finite element simulation, heating methods for
infrared radiators have been developed. Using the numeric
simulation many iteration loops are required to determine the process
parameters. Hence, the initiation of a model for calculating relevant
process parameters started applying regression functions.
Abstract: Next Generation Wireless Network (NGWN) is
expected to be a heterogeneous network which integrates all different
Radio Access Technologies (RATs) through a common platform. A
major challenge is how to allocate users to the most suitable RAT for
them. An optimized solution can lead to maximize the efficient use
of radio resources, achieve better performance for service providers
and provide Quality of Service (QoS) with low costs to users.
Currently, Radio Resource Management (RRM) is implemented
efficiently for the RAT that it was developed. However, it is not
suitable for a heterogeneous network. Common RRM (CRRM) was
proposed to manage radio resource utilization in the heterogeneous
network. This paper presents a user level Markov model for a three
co-located RAT networks. The load-balancing based and service
based CRRM algorithms have been studied using the presented
Markov model. A comparison for the performance of load-balancing
based and service based CRRM algorithms is studied in terms of
traffic distribution, new call blocking probability, vertical handover
(VHO) call dropping probability and throughput.
Abstract: Methods of clustering which were developed in the
data mining theory can be successfully applied to the investigation of
different kinds of dependencies between the conditions of
environment and human activities. It is known, that environmental
parameters such as temperature, relative humidity, atmospheric
pressure and illumination have significant effects on the human
mental performance. To investigate these parameters effect, data
mining technique of clustering using entropy and Information Gain
Ratio (IGR) K(Y/X) = (H(X)–H(Y/X))/H(Y) is used, where
H(Y)=-ΣPi ln(Pi). This technique allows adjusting the boundaries of
clusters. It is shown that the information gain ratio (IGR) grows
monotonically and simultaneously with degree of connectivity
between two variables. This approach has some preferences if
compared, for example, with correlation analysis due to relatively
smaller sensitivity to shape of functional dependencies. Variant of an
algorithm to implement the proposed method with some analysis of
above problem of environmental effects is also presented. It was
shown that proposed method converges with finite number of steps.
Abstract: To define or predict incipient motion in an alluvial
channel, most of the investigators use a standard or modified form of
Shields- diagram. Shields- diagram does give a process to determine
the incipient motion parameters but an iterative one. To design
properly (without iteration), one should have another equation for
resistance. Absence of a universal resistance equation also magnifies
the difficulties in defining the model. Neural network technique,
which is particularly useful in modeling a complex processes, is
presented as a tool complimentary to modeling incipient motion.
Present work develops a neural network model employing the RBF
network to predict the average velocity u and water depth y based on
the experimental data on incipient condition. Based on the model,
design curves have been presented for the field application.
Abstract: This paper presents the experimental as well as the
simulated performance studies on the transcritical CO2 heat pumps
for simultaneous water cooling and heating; effects of water mass
flow rates and water inlet temperatures of both evaporator and gas
cooler on the cooling and heating capacities, system COP and water
outlets temperatures are investigated. Study shows that both the
water mass flow rate and inlet temperature have significant effect on
system performances. Test results show that the effect of evaporator
water mass flow rate on the system performances and water outlet
temperatures is more pronounced (COP increases 0.6 for 1 kg/min)
compared to the gas cooler water mass flow rate (COP increases 0.4
for 1 kg/min) and the effect of gas cooler water inlet temperature is
more significant (COP decreases 0.48 for given ranges) compared to
the evaporator water inlet temperature (COP increases 0.43 for given
ranges). Comparisons of experimental values with simulated results
show the maximum deviation of 5% for cooling capacity, 10% for
heating capacity, 16% for system COP. This study offers useful
guidelines for selecting appropriate water mass flow rate to obtain
required system performance.
Abstract: The high world interest given to the researches concerning the study of moderately halophilic solvent-tolerant bacteria isolated from marine polluted environments is due to their high biotechnological potential, and also to the perspective of their application in different remediation technologies. Using enrichment procedures, I isolated two moderately halophilic Gram-negative bacterial strains from seawater sample, which are tolerant to organic solvents. Cell tolerance, adhesion and cells viability of Aeromonas salmonicida IBBCt2 and Pseudomonas aeruginosa IBBCt3 in the presence of organic solvents depends not only on its physicochemical properties and its concentration, but also on the specific response of the cells, and the cellular response is not the same for these bacterial strains. n-hexane, n-heptane, propylbenzene, with log POW between 3.69 and 4.39, were less toxic for Aeromonas salmonicida IBBCt2 and Pseudomonas aeruginosa IBBCt3, compared with toluene, styrene, xylene isomers and ethylbenzene, with log POW between 2.64 and 3.17. The results indicated that Aeromonas salmonicida IBBCt2 is more susceptible to organic solvents than Pseudomonas aeruginosa IBBCt3. The mechanisms underlying solvent tolerance (e.g., the existance of the efflux pumps) in Aeromonas salmonicida IBBCt2 and Pseudomonas aeruginosa IBBCt3 it was also studied.
Abstract: A highly optimized implementation of binary mixture
diffusion with no initial bulk velocity on graphics processors is
presented. The lattice Boltzmann model is employed for simulating
the binary diffusion of oxygen and nitrogen into each other with
different initial concentration distributions. Simulations have been
performed using the latest proposed lattice Boltzmann model that
satisfies both the indifferentiability principle and the H-theorem for
multi-component gas mixtures. Contemporary numerical
optimization techniques such as memory alignment and increasing
the multiprocessor occupancy are exploited along with some novel
optimization strategies to enhance the computational performance on
graphics processors using the C for CUDA programming language.
Speedup of more than two orders of magnitude over single-core
processors is achieved on a variety of Graphical Processing Unit
(GPU) devices ranging from conventional graphics cards to
advanced, high-end GPUs, while the numerical results are in
excellent agreement with the available analytical and numerical data
in the literature.
Abstract: Municipal solid waste (MSW) comprises of a wide
range of heterogeneous materials generated by individual, household
or organization and may include food waste, garden wastes, papers,
textiles, rubbers, plastics, glass, ceramics, metals, wood wastes,
construction wastes but it is not limited to the above mentioned
fractions. The most common Municipal Solid Waste pretreatment
method in use is thermal pretreatment (incineration) and Mechanical
Biological pretreatment. This paper presents an overview of these
two pretreatment methods describing their benefits and laboratory
scale reactors that simulate landfill conditions were constructed in
order to compare emissions in terms of biogas production and
leachate contamination between untreated Municipal Solid Waste and
Mechanical Biological Pretreated waste. The findings of this study
showed that Mechanical Biological pretreatment of waste reduces the
emission level of waste and the benefit over the landfilling of
untreated waste is significant.
Abstract: The paper presents new results of a recent industry
supported research and development study in which an efficient
framework for evaluating practical and meaningful power system
reliability and quality indices was applied. The system-wide
integrated performance indices are capable of addressing and
revealing areas of deficiencies and bottlenecks as well as
redundancies in the composite generation-transmission-demand
structure of large-scale power grids. The technique utilizes a linear
programming formulation, which simulates practical operating
actions and offers a general and comprehensive framework to assess
the harmony and compatibility of generation, transmission and
demand in a power system. Practical applications to a reduced
system model as well as a portion of the Saudi power grid are also
presented in the paper for demonstration purposes.
Abstract: The current of professional bicycle pedal-s
manufacturing model mostly used casting, forging, die-casting
processing methods, so the paper used 7075 aluminum alloy which is
to produce the bicycle parts most commonly, and employs the
rigid-plastic finite element (FE) DEFORMTM 3D software to simulate
and to analyze the professional bicycle pedal design. First we use Solid
works 2010 3D graphics software to design the professional bicycle
pedal of the mold and appearance, then import finite element (FE)
DEFORMTM 3D software for analysis. The paper used rigid-plastic
model analytical methods, and assuming mode to be rigid body. A
series of simulation analyses in which the variables depend on
different temperature of forging billet, friction factors, forging speed,
mold temperature are reveal to effective stress, effective strain, damage
and die radial load distribution for forging bicycle pedal. The analysis
results hope to provide professional bicycle pedal forming mold
references to identified whether suit with the finite element results for
high-strength design suitability of aluminum alloy.
Abstract: This paper presents a new method which applies an
artificial bee colony algorithm (ABC) for capacitor placement in
distribution systems with an objective of improving the voltage profile
and reduction of power loss. The ABC algorithm is a new population
based meta heuristic approach inspired by intelligent foraging behavior
of honeybee swarm. The advantage of ABC algorithm is that
it does not require external parameters such as cross over rate and
mutation rate as in case of genetic algorithm and differential evolution
and it is hard to determine these parameters in prior. The other
advantage is that the global search ability in the algorithm is implemented
by introducing neighborhood source production mechanism
which is a similar to mutation process. To demonstrate the validity
of the proposed algorithm, computer simulations are carried out on
69-bus system and compared the results with the other approach
available in the literature. The proposed method has outperformed the
other methods in terms of the quality of solution and computational
efficiency.
Abstract: Experiments have been carried out at the Latvia
University of Agriculture Department of Food Technology. The aim
of this work was to assess the effect of sous vide packaging during
the storage time of salad with meat in mayonnaise at different storage
temperature. Samples were evaluated at 0, 1, 3, 7, 10, 15, 18, 25, 29,
42, and 52 storage days at the storage temperature of +4±0.5 ºC and
+10±0.5 ºC. Experimentally the quality of the salad with meat in
mayonnaise was characterized by measuring colour, pH and
microbiological properties. The sous vide packaging was effective in
protecting the product from physical, chemical, and microbial quality
degradation. The sous vide packaging significantly reduces microbial
growth at storage temperature of +4±0.5 ºC and +10±0.5 ºC.
Moreover, it is possible to extend the product shelf life to 52 days
even when stored at +10±0.5 ºC.
Abstract: The present study was provided to examine the
vortical structures generated by two inclined impinging jets with
experimental and numerical investigations. The jets are issuing with a
pitch angle α=40° into a confined quiescent fluid. The experimental
investigation on flow patterns was visualized by using olive particles
injected into the jets illuminated by Nd:Yag laser light to reveal the
finer details of the confined jets interaction. It was observed that two
counter-rotating vortex pairs (CVPs) were generated in the near
region. A numerical investigation was also performed. First, the
numerical results were validates against the experimental results and
then the numerical model was used to study the effect of section ratio
on the evolution of the CVPs. Our results show promising agreement
with experimental data, and indicate that our model has the potential
to produce useful and accurate data regarding the evolution of CVPs.
Abstract: Direct numerical simulation (DNS) is used to study the evolution of a boundary layer that was laminar initially followed by separation and then reattachment owing to generation of turbulence. This creates a closed region of recirculation, known as the laminar-separation bubble. The present simulation emulates the flow environment encountered in a modern LP turbine blade, where a laminar separation bubble may occur on the suction surface. The unsteady, incompressible three-dimensional (3-D) Navier-Stokes (NS) equations have been solved over a flat plate in the Cartesian coordinates. The adverse pressure gradient, which causes the flow to separate, is created by a boundary condition. The separated shear layer undergoes transition through appearance of ╬ø vortices, stretching of these create longitudinal streaks. Breakdown of the streaks into small and irregular structures makes the flow turbulent downstream.
Abstract: In this paper, we proposed a novel receiver algorithm
for coherent underwater acoustic communications. The proposed
receiver is composed of three parts: (1) Doppler tracking and
correction, (2) Time reversal channel estimation and combining, and
(3) Joint iterative equalization and decoding (JIED). To reduce
computational complexity and optimize the equalization algorithm,
Time reversal (TR) channel estimation and combining is adopted to
simplify multi-channel adaptive decision feedback equalizer (ADFE)
into single channel ADFE without reducing the system performance.
Simultaneously, the turbo theory is adopted to form joint iterative
ADFE and convolutional decoder (JIED). In JIED scheme, the ADFE
and decoder exchange soft information in an iterative manner, which
can enhance the equalizer performance using decoding gain. The
simulation results show that the proposed algorithm can reduce
computational complexity and improve the performance of equalizer.
Therefore, the performance of coherent underwater acoustic
communications can be improved greatly.
Abstract: The equivalence class subset algorithm is a powerful
tool for solving a wide variety of constraint satisfaction problems and
is based on the use of a decision function which has a very high but
not perfect accuracy. Perfect accuracy is not required in the decision
function as even a suboptimal solution contains valuable information
that can be used to help find an optimal solution. In the hardest
problems, the decision function can break down leading to a
suboptimal solution where there are more equivalence classes than
are necessary and which can be viewed as a mixture of good decision
and bad decisions. By choosing a subset of the decisions made in
reaching a suboptimal solution an iterative technique can lead to an
optimal solution, using series of steadily improved suboptimal
solutions. The goal is to reach an optimal solution as quickly as
possible. Various techniques for choosing the decision subset are
evaluated.
Abstract: The lack of any centralized infrastructure in mobile ad
hoc networks (MANET) is one of the greatest security concerns in
the deployment of wireless networks. Thus communication in
MANET functions properly only if the participating nodes cooperate
in routing without any malicious intention. However, some of the
nodes may be malicious in their behavior, by indulging in flooding
attacks on their neighbors. Some others may act malicious by
launching active security attacks like denial of service. This paper
addresses few related works done on trust evaluation and
establishment in ad hoc networks. Related works on flooding attack
prevention are reviewed. A new trust approach based on the extent of
friendship between the nodes is proposed which makes the nodes to
co-operate and prevent flooding attacks in an ad hoc environment.
The performance of the trust algorithm is tested in an ad hoc network
implementing the Ad hoc On-demand Distance Vector (AODV)
protocol.