Abstract: The optimal operation of proton exchange membrane fuel cell (PEMFC) requires good water management which is presented under two forms vapor and liquid. Moreover, fuel cells have to reach higher output require integration of some accessories which need electrical power. In order to analyze fuel cells operation and different species transport phenomena a biphasic mathematical model is presented by governing equations set. The numerical solution of these conservation equations is calculated by Matlab program. A multi-criteria optimization with weighting between two opposite objectives is used to determine the compromise solutions between maximum output and minimal stack size. The obtained results are in good agreement with available literature data.
Abstract: In this article, the design of a Supply Chain Network
(SCN) consisting of several suppliers, production plants, distribution
centers and retailers, is considered. Demands of retailers are
considered stochastic parameters, so we generate amounts of data via
simulation to extract a few demand scenarios. Then a mixed integer
two-stage programming model is developed to optimize
simultaneously two objectives: (1) minimization the fixed and
variable cost, (2) maximization the service level. A weighting method
is utilized to solve this two objective problem and a numerical
example is made to show the performance of the model.
Abstract: Assembly line balancing is a very important issue in
mass production systems due to production cost. Although many
studies have been done on this topic, but because assembly line
balancing problems are so complex they are categorized as NP-hard
problems and researchers strongly recommend using heuristic
methods. This paper presents a new heuristic approach called the
critical task method (CTM) for solving U-shape assembly line
balancing problems. The performance of the proposed heuristic
method is tested by solving a number of test problems and comparing
them with 12 other heuristics available in the literature to confirm the
superior performance of the proposed heuristic. Furthermore, to
prove the efficiency of the proposed CTM, the objectives are
increased to minimize the number of workstation (or equivalently
maximize line efficiency), and minimizing the smoothness index.
Finally, it is proven that the proposed heuristic is more efficient than
the others to solve the U-shape assembly line balancing problem.
Abstract: In this era of technology, fueled by the pervasive usage of the internet, security is a prime concern. The number of new attacks by the so-called “bots", which are automated programs, is increasing at an alarming rate. They are most likely to attack online registration systems. Technology, called “CAPTCHA" (Completely Automated Public Turing test to tell Computers and Humans Apart) do exist, which can differentiate between automated programs and humans and prevent replay attacks. Traditionally CAPTCHA-s have been implemented with the challenge involved in recognizing textual images and reproducing the same. We propose an approach where the visual challenge has to be read out from which randomly selected keywords are used to verify the correctness of spoken text and in turn detect the presence of human. This is supplemented with a speaker recognition system which can identify the speaker also. Thus, this framework fulfills both the objectives – it can determine whether the user is a human or not and if it is a human, it can verify its identity.
Abstract: Numerical studies have been carried out using a two
dimensional code to examine the influence of pressure / thrust
transient of solid propellant rockets at liftoff. This code solves
unsteady Reynolds-averaged thin-layer Navier–Stokes equations by
an implicit LU-factorization time-integration method. The results
from the parametric study indicate that when the port is narrow there
is a possibility of increase in pressure / thrust-rise rate due to
relatively high flame spread rate. Parametric studies further reveal
that flame spread rate can be altered by altering the propellant
properties, igniter jet characteristics and nozzle closure burst pressure
without altering the grain configuration and/or the mission
demanding thrust transient. We observed that when the igniter
turbulent intensity is relatively low the vehicle could liftoff early due
to the early flow choking of the rocket nozzle. We concluded that the
high pressurization-rate has structural implications at liftoff in
addition to transient burning effect. Therefore prudent selection of the
port geometry and the igniter, for meeting the mission requirements,
within the given envelop are meaningful objectives for any designer
for the smooth liftoff of solid propellant rockets.
Abstract: The aim of this study was to establish the relationship between the principles of Educational Sport and the objectives of Physical Education in two brasilian laws: National Curriculum Guidelines (PCNs) for the Elementary and Middle School Levels and the Guidelines and Basis Legislation (LDB). The method used was the survey analysis in order to determine the practices present in, or the opinions of, a specific population. The instrument used in this research was a questionnaire. After a broad review of the bibliography and according to the methodological procedures, the aim was to set the relationships between the Principles of Educational Sport and the objectives of Physical Education, according to the Brazilian Law (LDB) and National Curriculum Guidelines (PCNs) in a table made under the analysis of a group of specialists. As the relation between the principles of Educational Sport and the objectives of School Physical Education have shown, we can state that School Physical Education has gained pedagogical security for the potential use of Educational Sport as part of its contents.
Abstract: The objectives of the study are to examine the
determinants of ERP implementation success factors of ERP
implementation. The result indicates that large scale ERP
implementation success consist of eight factors: project management
competence, knowledge sharing, ERP system quality , understanding,
user involvement, business process re-engineering, top management
support, organization readiness.
Abstract: Bubble columns have a variety of applications in
absorption, bio-reactions, catalytic slurry reactions, and coal
liquefaction; because they are simple to operate, provide good heat
and mass transfer, having less operational cost. The use of
Computational Fluid Dynamics (CFD) for bubble column becomes
important, since it can describe the fluid hydrodynamics on both local
and global scale. Euler- Euler two-phase fluid model has been used to
simulate two-phase (air and water) transient up-flow in bubble
column (15cm diameter) using FLUENT6.3. These simulations and
experiments were operated over a range of superficial gas velocities
in the bubbly flow and churn turbulent regime (1 to16 cm/s) at
ambient conditions. Liquid velocity was varied from 0 to 16cm/s. The
turbulence in the liquid phase is described using the standard k-ε
model. The interactions between the two phases are described
through drag coefficient formulations (Schiller Neumann). The
objectives are to validate CFD simulations with experimental data,
and to obtain grid-independent numerical solutions. Quantitatively
good agreements are obtained between experimental data for hold-up
and simulation values. Axial liquid velocity profiles and gas holdup
profiles were also obtained for the simulation.
Abstract: To make use of the limited amounts of water in arid
region, the Iranians developed man-made underground water
channels called qanats (kanats) .In fact, qanats may be considered as
the first long-distance water transfer system. Qanats are an ancient
water transfer system found in arid regions wherein groundwater
from mountainous areas, aquifers and sometimes from rivers, was
brought to points of re-emergence such as an oasis, through one or
more underground tunnels. The tunnels, many of which were
kilometers in length, had designed for slopes to provide gravitational
flow. The tunnels allowed water to drain out to the surface by gravity
to supply water to lower and flatter agricultural land.
Qanats have been an ancient, sustainable system facilitating the
harvesting of water for centuries in Iran, and more than 35 additional
countries of the world such as India, Arabia, Egypt, North Africa,
Spain and even to New world.
There are about 22000 qanats in Iran with 274000 kilometers of
underground conduits all built by manual labor. The amount of
water of the usable qanats of Iran produce is altogether 750 to
1000 cubic meter per second. The longest chain of qanat is
situated in Gonabad region in Khorasan province. It is 70
kilometers long. Qanats are renewable water supply systems that
have sustained agricultural settlement on the Iranian plateau for
millennia. The great advantages of Qanats are no evaporation
during transit, little seepage , no raising of the water- table and no
pollution in the area surrounding the conduits. Qanat systems
have a profound influence on the lives of the water users in Iran, and
conform to Iran-s climate. Qanat allows those living in a desert
environment adjacent to a mountain watershed to create a large oasis
in an otherwise stark environment.
This paper explains qanats structure designs, their history,
objectives causing their creation, construction materials, locations
and their importance in different times, as well as their present
sustainable role in Iran.
Abstract: Extensive rainfall disaggregation approaches have been developed and applied in climate change impact studies such as flood risk assessment and urban storm water management.In this study, five rainfall models that were capable ofdisaggregating daily rainfall data into hourly one were investigated for the rainfall record in theChangi Airport, Singapore. The objectives of this study were (i) to study the temporal characteristics of hourly rainfall in Singapore, and (ii) to evaluate the performance of variousdisaggregation models. The used models included: (i) Rectangular pulse Poisson model (RPPM), (ii) Bartlett-Lewis Rectangular pulse model (BLRPM), (iii) Bartlett-Lewis model with 2 cell types (BL2C), (iv) Bartlett-Lewis Rectangular with cell depth distribution dependent on duration (BLRD), and (v) Neyman-Scott Rectangular pulse model (NSRPM). All of these models werefitted using hourly rainfall data ranging from 1980 to 2005 (which was obtained from Changimeteorological station).The study results indicated that the weight scheme of inversely proportional variance could deliver more accurateoutputs for fitting rainfall patterns in tropical areas, and BLRPM performedrelatively better than other disaggregation models.
Abstract: Environmental responsibility includes improvement of environmental performance in order to reduce environmental impact. This paper gives a short review of some important environmental objectives, targets and actions that modern shipping company should follow.
Abstract: Combining energy efficiency with renewable energy
sources constitutes a key strategy for a sustainable future. The wind
power sector stands out as a fundamental element for the
achievement of the European renewable objectives and Portugal is no
exception to the increase of the wind energy for the electricity
generation. This work proposes an optimization model for the long
range electricity power planning in a system similar to the
Portuguese one, where the expected impacts of the increasing
installed wind power on the operating performance of thermal power
plants are taken into account. The main results indicate that the
increasing penetration of wind power in the electricity system will
have significant effects on the combined cycle gas power plants
operation and on the theoretically expected cost reduction and
environmental gains. This research demonstrated the need to address
the impact that energy sources with variable output may have, not
only on the short-term operational planning, but especially on the
medium to long range planning activities, in order to meet the
strategic objectives for the energy sector.
Abstract: This paper presents a multi-objective model for addressing two main objectives in designing rural roads networks: minimization of user operation costs and maximization of population covered. As limited budgets often exist, a reasonable trade-off must be obtained in order to account for both cost and social benefits in this type of networks. For a real-world rural road network, the model is solved, where all non-dominated solutions were obtained. Afterwards, an analysis is made on the (possibly) most interesting solutions (the ones providing better trade-offs). This analysis, coupled with the knowledge of the real world scenario (typically provided by decision makers) provides a suitable method for the evaluation of road networks in rural areas of developing countries.
Abstract: It-s difficult for China-s current land transfer
institutions limited to county-wide to solve the contradiction between
urban-rural development and construction land shortage. On the basis of analyzing China-s construction land transfer system, and evaluation
toward Transfer of development rights (TDR) practices in Anhui and
Chongqing, the passage proposes: (1) we should establish a multi-level
land indicators trade market under the guidance of regional spatial
objectives, and allow land transfer paid across cities and counties
within a specific area following the regulation of both government and
market; (2) it would be better to combine organically the policy ntentions of land plan, regional plan, urban plan and economic plan, and link them with land indicators transfer to promote a wider range of
urban-rural balance and regional coordination.
Abstract: In recent years, “Bottom-up Planning Approach" has been widely accepted and expanded from planning theorists. Citizen participation becomes more important in decision-making in informal settlements. Many of previous projects and strategies due to ignorance of citizen participation, have been failed facing with informal settlements and in some cases lead physical expansion of these neighbourhoods. According to recent experiences, the new participatory approach was in somehow successful. This paper focuses on local experiences in Iran. A considerable amount of people live in informal settlements in Iran. With the previous methods, the government could not solve the problems of these settlements. It is time to examine new methods such as empowerment of the local citizens and involve them to solve the current physical, social, and economic problems. The paper aims to address the previous and new strategies facing with informal settlements, the conditions under which citizens could be involved in planning process, limits and potentials of this process, the main actors and issues and finally motivations that are able to promote citizen participation. Documentary studies, observation, interview and questionnaire have been used to achieve the above mentioned objectives. Nearly 80 percent of responder in Saadi Community are ready to participate in regularising their neighbourhoods, if pre-conditions of citizen involvement are being provided. These pre-conditions include kind of problem and its severity, the importance of issue, existence of a short-term solution, etc. Moreover, confirmation of dweller-s ownership can promote the citizen engagement in participatory projects.
Abstract: In this paper the multi-mode resource-constrained project scheduling problem with discounted cash flows is considered. Minimizing the makespan and maximization the net present value (NPV) are the two common objectives that have been investigated in the literature. We apply one evolutionary algorithm named multiobjective particle swarm optimization (MOPSO) to find Pareto front solutions. We used standard sets of instances from the project scheduling problem library (PSPLIB). The results are computationally compared respect to different metrics taken from the literature on evolutionary multi-objective optimization.
Abstract: Nowadays, efficiency, effectiveness and economy are regarded as the main objectives of managers and the secret of the continuity of an organization in competing economy. In such competing settings, it is essential that the management of an organization has not been neglected and been obliged to identify quickly the opportunities for improving the operation of organization and remove the shortcomings of their managed system in order to use the opportunities for development. Operational auditing is a useful tool for system adjustment and leading an organization toward its objectives. Operational auditing is indeed a viewpoint which identifies the causes of insufficiencies, weaknesses and deficiencies of system and plans to eliminate them. Operational auditing is useful in the effectiveness and optimization of executive managers- decisions and increasing the efficiency and economy of their performance in the future and prevents the waste and incorrect use of resources. Evidence shows that operational auditing is used at a limited level in Iran. This matter raises some questions like the following ones in the minds. Why do a limited number of corporations use operational auditing? Which factors can guarantee its full implementation? What obstacles are there in its implementation? The purpose of this article is to determine executive objectives, the operation domain of operational auditing, the components of operational auditing and the executive obstacles to operational auditing in Iran.
Abstract: The shortest path routing problem is a multiobjective nonlinear optimization problem with constraints. This problem has been addressed by considering Quality of service parameters, delay and cost objectives separately or as a weighted sum of both objectives. Multiobjective evolutionary algorithms can find multiple pareto-optimal solutions in one single run and this ability makes them attractive for solving problems with multiple and conflicting objectives. This paper uses an elitist multiobjective evolutionary algorithm based on the Non-dominated Sorting Genetic Algorithm (NSGA), for solving the dynamic shortest path routing problem in computer networks. A priority-based encoding scheme is proposed for population initialization. Elitism ensures that the best solution does not deteriorate in the next generations. Results for a sample test network have been presented to demonstrate the capabilities of the proposed approach to generate well-distributed pareto-optimal solutions of dynamic routing problem in one single run. The results obtained by NSGA are compared with single objective weighting factor method for which Genetic Algorithm (GA) was applied.
Abstract: It is the living conditions in the cities that determine the future of our livelihood. “To change life, we must first change space"- Henri Lefebvre. Sustainable development is a utopian aspiration for South African cities (especially the case study of the Gauteng City Region), which are currently characterized by unplanned growth and increasing urban sprawl. While the reasons for poor environmental quality and living conditions are undoubtedly diverse and complex, having political, economical and social dimensions, it is argued that the prevailing approach to layout planning in South Africa is part of the problem. This article seeks a solution to the problem of sustainability, from a spatial planning perspective. The spatial planning tool, the urban development boundary, is introduced as the concept that will ensure empty talk being translated into a sustainable vision. The urban development boundary is a spatial planning tool that can be used and implemented to direct urban growth towards a more sustainable form. The urban development boundary aims to ensure planned urban areas, in contrast to the current unplanned areas characterized by urban sprawl and insufficient infrastructure. However, the success of the urban development boundary concept is subject to effective implementation measures, as well as adequate and efficient management. The concept of sustainable development can function as a driving force underlying societal change and transformation, but the interface between spatial planning and environmental management needs to be established (as this is the core aspects underlying sustainable development), and authorities needs to understand and implement this interface consecutively. This interface can, however, realize in terms of the objectives of the planning tool – the urban development boundary. The case study, the Gauteng City Region, is depicted as a site of economic growth and innovation, but there is a lack of good urban and regional governance, impacting on the design (layout) and function of urban areas and land use, as current authorities make uninformed decisions in terms of development applications, leading to unsustainable urban forms and unsustainable nodes. Place and space concepts are thus critical matters applicable to planning of the Gauteng City Region. The urban development boundary are thus explored as a planning tool to guide decision-making, and create a sustainable urban form, leading to better environmental and living conditions, and continuous sustainability.
Abstract: Supplier appraisal fosters energy in Supply Chain
Management and helps in best optimization of viable business
partners for a company. Many Decision Making techniques have
already been proposed by researchers for supplier-s appraisal.
However, Analytic Hierarchy Process (AHP) is assumed to be the
most structured technique to attain near-best solution of the problem.
This paper focuses at implementation of AHP in the procurement
processes. It also suggests that on what factors a Public Sector
Enterprises must focus while dealing with their suppliers and what
should the suppliers do to synchronize their activities with the
strategic objectives of Organization. It also highlights the weak areas
in supplier appraisal process with a view to suggest viable
recommendations.