Abstract: In order to achieve high data rate and increase the
spectral efficiency, multiple input multiple output (MIMO) system has
been proposed. However, multiple antennas are limited by size and
cost. Therefore, recently developed cooperative diversity scheme,
which profits the transmit diversity only with the existing hardware by
constituting a virtual antenna array, can be a solution. However, most
of the introduced cooperative techniques have a common fault of
decreased transmission rate because the destination should receive the
decodable compositions of symbols from the source and the relay. In
this paper, we propose a cooperative cyclic delay diversity (CDD)
scheme that use hierarchical modulation. This scheme is free from the
rate loss and allows seamless cooperative communication.
Abstract: In insulation and cooling of power transformers
various liquids are used. Mineral oils have wide availability and low
cost. However, they have a poor biodegradability potential and lower
fire point in comparison with other insulating liquids. Use of a liquid
having high biodegradability is important due to environmental
consideration. This paper investigates edible corn oil as an alternative
to mineral oil. Various properties of mineral and corn oil like
breakdown voltage, dissipation factor, relative dielectric constant,
power loss and resistivity were measured according to different
standards.
Abstract: This paper introduces a boost converter with a new
active snubber cell. In this circuit, all of the semiconductor
components in the converter softly turns on and turns off with the
help of the active snubber cell. Compared to the other converters, the
proposed converter has advantages of size, number of components
and cost. The main feature of proposed converter is that the extra
voltage stresses do not occur on the main switches and main diodes.
Also, the current stress on the main switch is acceptable level.
Moreover, the proposed converter can operates under light load
conditions and wide input line voltage. In this study, the operating
principle of the proposed converter is presented and its operation is
verified with the Proteus simulation software for a 1 kW and 100 kHz
model.
Abstract: The MEMS pressure sensor has been introduced and
presented in this paper. The types of pressure sensor and its theory of
operation are also included. The latest MEMS technology, the
fabrication processes of pressure sensor are explored and discussed.
Besides, various device applications of pressure sensor such as tire
pressure-monitoring system, diesel particulate filter and others are
explained. Due to further miniaturization of the device nowadays, the
pressure sensor with nanotechnology (NEMS) is also reviewed. The
NEMS pressure sensor is expected to have better performance as well
as lower in its cost. It has gained an excellent popularity in many
applications.
Abstract: In present global scenario, aluminum alloys are
coining the attention of many innovators as competing structural
materials for automotive and space applications. Comparing to other
challenging alloys, especially, 7xxx series aluminum alloys have
been studied seriously because of benefits such as moderate strength;
better deforming characteristics and affordable cost. It is expected
that substitution of aluminum alloys for steels will result in great
improvements in energy economy, durability and recyclability.
However, it is necessary to improve the strength and the formability
levels at low temperatures in aluminum alloys for still better
applications. Aluminum–Zinc–Magnesium with or without other
wetting agent denoted as 7XXX series alloys are medium strength
heat treatable alloys. In addition to Zn, Mg as major alloying
additions, Cu, Mn and Si are the other solute elements which
contribute for the improvement in mechanical properties by suitable
heat treatment process. Subjecting to suitable treatments like age
hardening or cold deformation assisted heat treatments; known as low
temperature thermomechanical treatments (LTMT) the challenging
properties might be incorporated. T6 is the age hardening or
precipitation hardening process with artificial aging cycle whereas T8
comprises of LTMT treatment aged artificially with X% cold
deformation. When the cold deformation is provided after solution
treatment, there is increase in hardness related properties such as
wear resistance, yield and ultimate strength, toughness with the
expense of ductility. During precipitation hardening both hardness
and strength of the samples are increasing. The hardness value may
further improve when room temperature deformation is positively
supported with age hardening known as thermomechanical treatment.
It is intended to perform heat treatment and evaluate hardness, tensile
strength, wear resistance and distribution pattern of reinforcement in
the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported
in age hardening and LTMT treatments respectively as compared to
as-cast composite. There was better distribution of reinforcements in
the matrix, nearly two fold increase in strength levels and up to 5
times increase in wear resistance are also observed in the present
study.
Abstract: In this paper we propose a computer-aided solution
with Genetic Algorithms in order to reduce the drafting of reports:
FMEA analysis and Control Plan required in the manufacture of the
product launch and improved knowledge development teams for
future projects. The solution allows to the design team to introduce
data entry required to FMEA. The actual analysis is performed using
Genetic Algorithms to find optimum between RPN risk factor and
cost of production. A feature of Genetic Algorithms is that they are
used as a means of finding solutions for multi criteria optimization
problems. In our case, along with three specific FMEA risk factors is
considered and reduce production cost. Analysis tool will generate
final reports for all FMEA processes. The data obtained in FMEA
reports are automatically integrated with other entered parameters in
Control Plan. Implementation of the solution is in the form of an
application running in an intranet on two servers: one containing
analysis and plan generation engine and the other containing the
database where the initial parameters and results are stored. The
results can then be used as starting solutions in the synthesis of other
projects. The solution was applied to welding processes, laser cutting
and bending to manufacture chassis for buses. Advantages of the
solution are efficient elaboration of documents in the current project
by automatically generating reports FMEA and Control Plan using
multiple criteria optimization of production and build a solid
knowledge base for future projects. The solution which we propose is
a cheap alternative to other solutions on the market using Open
Source tools in implementation.
Abstract: In a practical power system, the power plants are not
located at the same distance from the center of loads and their fuel
costs are different. Also, under normal operating conditions, the
generation capacity is more than the total load demand and losses.
Thus, there are many options for scheduling generation. In an
interconnected power system, the objective is to find the real and
reactive power scheduling of each power plant in such a way as to
minimize the operating cost. This means that the generator’s real and
reactive powers are allowed to vary within certain limits so as to meet
a particular load demand with minimum fuel cost. This is called
optimal power flow problem. In this paper, Economic Load Dispatch
(ELD) of real power generation is considered. Economic Load
Dispatch (ELD) is the scheduling of generators to minimize total
operating cost of generator units subjected to equality constraint of
power balance within the minimum and maximum operating limits of
the generating units. In this paper, genetic algorithms are considered.
ELD solutions are found by solving the conventional load flow
equations while at the same time minimizing the fuel costs.
Abstract: Mass media campaigns against obesity are often
designed to impact large audiences. This usually means that their
audience is defined based on general demographic characteristics like
age, gender, occupation etc., not taking into account psychographics
like behavior, motivations, wants, etc. Using psychographics, as the
base for the audience segmentation, is a common practice in case of
successful campaigns, as it allows developing more relevant
messages. It also serves a purpose of identifying key segments, those
that generate the best return on investment. For a health campaign,
that would be segments that have the best chance of being converted
into healthy lifestyle at the lowest cost. This paper presents the
limitations of the demographic targeting, based on the findings from
the reception study of IMSS (Mexican Social Security Institute) antiobesity
TV commercials and proposes mothers as the first level of
segmentation, in the process of identifying the key segment for these
campaigns.
Abstract: Wavelength Division Multiplexing (WDM) is the dominant transport technology used in numerous high capacity backbone networks, based on optical infrastructures. Given the importance of costs (CapEx and OpEx) associated to these networks, resource management is becoming increasingly important, especially how the optical circuits, called “lightpaths”, are routed throughout the network. This requires the use of efficient algorithms which provide routing strategies with the lowest cost. We focus on the lightpath routing and wavelength assignment problem, known as the RWA problem, while optimizing wavelength fragmentation over the network. Wavelength fragmentation poses a serious challenge for network operators since it leads to the misuse of the wavelength spectrum, and then to the refusal of new lightpath requests. In this paper, we first establish a new Integer Linear Program (ILP) for the problem based on a node-link formulation. This formulation is based on a multilayer approach where the original network is decomposed into several network layers, each corresponding to a wavelength. Furthermore, we propose an efficient heuristic for the problem based on a greedy algorithm followed by a post-treatment procedure. The obtained results show that the optimal solution is often reached. We also compare our results with those of other RWA heuristic methods
Abstract: The thermal performance of a solar water heating with
1.00 m2 flat plate collectors in Cascavel - PR, is which presented in
this article, paper presents the solution to leverage the marketing of
solar heating systems through detailed constituent materials of the
solar collector studies, these abundant materials in construction, such
as expanded polyethylene, PVC, aluminum and glass tubes, mixing
them with new materials to minimize loss of efficiency while
decreasing its cost. The system was tested during months and the
collector obtained maximum recorded temperature of outlet fluid of
55°C, while the maximum temperature of the water at the bottom of
the hot water tank was 35°C. The average daily energy collected was
19.6 MJ/d; the energy supplied by the solar plate was 16.2 MJ/d; the
loss in the feed pipe was 3.2 MJ/d; the solar fraction was 32.2%, the
efficiency of the collector was 45.6% and the efficiency of the system
was 37.8%.
Abstract: The Markov decision process (MDP) based
methodology is implemented in order to establish the optimal
schedule which minimizes the cost. Formulation of MDP problem
is presented using the information about the current state of pipe,
improvement cost, failure cost and pipe deterioration model. The
objective function and detailed algorithm of dynamic programming
(DP) are modified due to the difficulty of implementing the
conventional DP approaches. The optimal schedule derived from
suggested model is compared to several policies via Monte
Carlo simulation. Validity of the solution and improvement in
computational time are proved.
Abstract: One of the best examples, in evolution of the public
procurement, from post-soviet countries are reforms carried out in
Georgia, which brought them close to international standards of
procurement. In Georgia, public procurement legislation started
functioning short after gaining independence. The reform has passed
several stages and came in the form as it is today. It should also be
noted, that countries with economy in transition, including Georgia,
implemented all the reforms in public procurement based on
recommendations and support of World Bank, the United Nations
and other international organizations.
The aim of first adopted law was regulation of the procurement
process of budget-organizations, transparency and creation of
competitive environment for private companies to access state funds
legally. The priorities were identified quite clearly in the wording of
the law, but operation/function of this law could not be reached on its
level, because of some objective and subjective reasons. The high
level of corruption in all levels of governance can be considered as a
main obstacle reason and of course, it is natural, that it had direct
impact on the procurement process, as well as on transparency and
rational use of state funds. These circumstances were the reasons that
reforms in this sphere continued, to improve procurement process, in
particular, the first wave of reforms began after several years. Public
procurement agency carried out reform with World Bank with main
purpose of smartening the procurement legislation and its
harmonization with international treaties and agreements. Also with
the support of World Bank various activities were carried out to raise
awareness of participants involved in procurement system.
Further major changes in the legislation were filed bit later, which
was also directed towards the improvement and smarten of the
procurement process. The third wave of the reform more or less
guaranteed the transparency of the procurement process, which later
became the basis for the rational spending of state funds. The reform
of the procurement system completely changed the procedures.
Carried out reform in Georgia resulted in introducing new
electronic tendering system, which benefit the transparency of the
process, after this became the basis for the further development of a
competitive environment, which become a prerequisite for the state
rational spending. Increased number of supplier organizations
participating in the procurement process resulted in reduction of the
estimated cost and the actual cost.
Assessment of the reforms in Georgia in the field of public
procurement can be concluded, that proper regulation of the sector
and relevant policy may proceed to rational and transparent spending
of the budget from country’s state institutions. Also, the business
sector has the opportunity to work in competitive market conditions
and to make a preliminary analysis, which is a prerequisite for future
strategy and development.
Abstract: Wind energy offers a significant advantage such as no
fuel costs and no emissions from generation. However, wind energy
sources are variable and non-dispatchable. The utility grid is able to
accommodate the variability of wind in smaller proportion along with
the daily load. However, at high penetration levels, the variability can
severely impact the utility reserve requirements and the cost
associated with it. In this paper the impact of wind energy is
evaluated in detail in formulating the total utility cost. The objective
is to minimize the overall cost of generation while ensuring the
proper management of the load. Overall cost includes the curtailment
cost, reserve cost and the reliability cost, as well as any other penalty
imposed by the regulatory authority. Different levels of wind
penetrations are explored and the cost impacts are evaluated. As the
penetration level increases significantly, the reliability becomes a
critical question to be answered. Here we increase the penetration
from the wind yet keep the reliability factor within the acceptable
limit provided by NERC. This paper uses an economic dispatch (ED)
model to incorporate wind generation into the power grid. Power
system costs are analyzed at various wind penetration levels using
Linear Programming. The goal of this study is show how the
increases in wind generation will affect power system economics.
Abstract: ESPRIT-TLS method appears a good choice for high
resolution fault detection in induction machines. It has a very high
effectiveness in the frequency and amplitude identification.
Contrariwise, it presents a high computation complexity which
affects its implementation in real time fault diagnosis. To avoid this
problem, a Fast-ESPRIT algorithm that combined the IIR band-pass
filtering technique, the decimation technique and the original
ESPRIT-TLS method was employed to enhance extracting accurately
frequencies and their magnitudes from the wind stator current with
less computation cost. The proposed algorithm has been applied to
verify the wind turbine machine need in the implementation of an online,
fast, and proactive condition monitoring. This type of remote
and periodic maintenance provides an acceptable machine lifetime,
minimize its downtimes and maximize its productivity. The
developed technique has evaluated by computer simulations under
many fault scenarios. Study results prove the performance of Fast-
ESPRIT offering rapid and high resolution harmonics recognizing
with minimum computation time and less memory cost.
Abstract: The web’s increased popularity has included a huge
amount of information, due to which automated web page
classification systems are essential to improve search engines’
performance. Web pages have many features like HTML or XML
tags, hyperlinks, URLs and text contents which can be considered
during an automated classification process. It is known that Webpage
classification is enhanced by hyperlinks as it reflects Web page
linkages. The aim of this study is to reduce the number of features to
be used to improve the accuracy of the classification of web pages. In
this paper, a novel feature selection method using an improved
Particle Swarm Optimization (PSO) using principle of evolution is
proposed. The extracted features were tested on the WebKB dataset
using a parallel Neural Network to reduce the computational cost.
Abstract: The industrial process adds to engineering wood
products features absent in solid wood, with homogeneous structure
and reduced defects, improved physical and mechanical properties,
bio-deterioration, resistance and better dimensional stability,
improving quality and increasing the reliability of structures wood.
These features combined with using fast-growing trees, make them
environmentally ecological products, ensuring a strong consumer
market. The wood I-joists are manufactured by the industrial profiles
bonding flange and web, an important aspect of the production of
wooden I-beams is the adhesive joint that bonds the web to the
flange. Adhesives can effectively transfer and distribute stresses,
thereby increasing the strength and stiffness of the composite. The
objective of this study is to evaluate different resins in a shear strain
specimens with the aim of analyzing the most efficient resin and
possibility of using national products, reducing the manufacturing
cost. First was conducted a literature review, where established the
geometry and materials generally used, then established and analyzed
8 national resins and produced six specimens for each.
Abstract: Iran has several potential for using renewable
energies, so use them could significantly contribute to energy supply.
The purpose of this paper is to identify the potential of the country
and select the appropriate DG technologies with consideration the
potential and primary energy resources in the regions. In this context,
hybrid energy systems proportionate with the potential of different
regions will be determined based on technical, economic, and
environmental aspect. In the following the proposed structure will be
optimized in terms of size and cost. DG technologies used in this
project include photovoltaic system, wind turbine, diesel generator
and battery bank. The HOMER software is applied for choosing the
appropriate structure and the optimization of system sizing. The
results have been analyzed in terms of technical and economic. The
performance and the cost of each project demonstrate the appropriate
structure of hybrid energy system in that region.
Abstract: Managing and improving efficiency in the current
highly competitive global automotive industry demands that those
companies adopt leaner and more flexible systems. During the past
20 years the domestic automotive industry in North America has been
focusing on establishing new management strategies in order to meet
market demands. The lean management process also known as
Toyota Manufacturing Process (TPS) or lean manufacturing
encompasses tools and techniques that were established in order to
provide the best quality product with the fastest lead time at the
lowest cost. The following paper presents a study that focused on
improving labor efficiency at one of the Big Three (Ford, GM,
Chrysler LLC) domestic automotive facility in North America. The
objective of the study was to utilize several lean management tools in
order to optimize the efficiency and utilization levels at the “Pre-
Marriage” chassis area in a truck manufacturing and assembly
facility. Utilizing three different lean tools (i.e. Standardization of
work, 7 Wastes, and 5S) this research was able to improve efficiency
by 51%, utilization by 246%, and reduce operations by 14%. The
return on investment calculated based on the improvements made
was 284%.
Abstract: Construction cost estimation is one of the most
important aspects of construction project design. For generations, the
process of cost estimating has been manual, time-consuming and
error-prone. This has partly led to most cost estimates to be unclear
and riddled with inaccuracies that at times lead to over- or underestimation
of construction cost. The development of standard set of
measurement rules that are understandable by all those involved in a
construction project, have not totally solved the challenges. Emerging
Building Information Modelling (BIM) technologies can exploit
standard measurement methods to automate cost estimation process
and improve accuracies. This requires standard measurement
methods to be structured in ontological and machine readable format;
so that BIM software packages can easily read them. Most standard
measurement methods are still text-based in textbooks and require
manual editing into tables or Spreadsheet during cost estimation. The
aim of this study is to explore the development of an ontology based
on New Rules of Measurement (NRM) commonly used in the UK for
cost estimation. The methodology adopted is Methontology, one of
the most widely used ontology engineering methodologies. The
challenges in this exploratory study are also reported and
recommendations for future studies proposed.
Abstract: Composite materials, due to their unique properties
such as high strength to weight ratio, corrosion resistance, and impact
resistance have huge potential as structural materials in automotive,
construction and transportation applications. However, these
properties often come at higher cost owing to complex design
methods, difficult manufacturing processes and raw material cost.
Traditionally, tapered laminated composite structures are
manufactured using autoclave manufacturing process by ply drop off
technique. Autoclave manufacturing though very powerful suffers
from high capital investment and higher energy consumption. As per
the current trends in composite manufacturing, Out of Autoclave
(OoA) processes are looked as emerging technologies for
manufacturing the structural composite components for aerospace
and defense applications. However, there is a need for improvement
among these processes to make them reliable and consistent. In this
paper, feasibility of using out of autoclave process to manufacture the
variable thickness cantilever beam is discussed. The minimum weight
design for the composite beam is obtained using constant stress beam
concept by tailoring the thickness of the beam. Ply drop off
techniques was used to fabricate the variable thickness beam from
glass/epoxy prepregs. Experiments were conducted to measure
bending stresses along the span of the cantilever beam at different
intervals by applying the concentrated load at the free end.
Experimental results showed that the stresses in the bean at different
intervals were constant. This proves the ability of OoA process to
manufacture the constant stress beam. Finite element model for the
constant stress beam was developed using commercial finite element
simulation software. It was observed that the simulation results
agreed very well with the experimental results and thus validated
design and manufacturing approach used.