Abstract: Wireless Mesh Networks (WMNs) are an emerging
technology for last-mile broadband access. In WMNs, similar to ad
hoc networks, each user node operates not only as a host but also as a
router. User packets are forwarded to and from an Internet-connected
gateway in multi-hop fashion. The WMNs can be integrated with
other networking technologies i.e. ad hoc networks, to implement a
smooth network extension. The meshed topology provides good
reliability and scalability, as well as low upfront investments. Despite
the recent start-up surge in WMNs, much research remains to be
done in standardizing the functional parameters of WMNs to fully
exploit their full potential. An edifice of the security concerns of
these networks is authentication of a new client joining an integrated
ad hoc network and such a scenario will require execution of a multihop
authentication technique. Our endeavor in this paper is to
introduce a secure authentication technique, with light over-heads
that can be conveniently implemented for the ad-hoc nodes forming
clients of an integrated WMN, thus facilitating their inter-operability.
Abstract: In this paper, the test purpose will be to assess
whether or not the accelerated model proposed by Eyring will be able
to translate results for the shape and scale parameters of an
underlying Weibull model, obtained under two accelerating using
conditions, to expected normal using condition results for these
parameters. The product being analyzed is a new type of insulate
fluid, and the accelerating factor is the voltage stresses applied to the
fluid at two different levels (30KV and 40KV). The normal operating
voltage is 25KV. In this case, it was possible to test the insulate fluid
at normal voltage using condition. Both results for the two
parameters of the Weibull model, obtained under normal using
condition and translated from accelerated using conditions to normal
conditions, will be compared to each other to assess the accuracy of
the Eyring model when the accelerating factor is only the voltage
stress.
Abstract: This paper presents the development of an MODAPTS based cost estimating system to help designers in estimating the manufacturing cost of a assembly products which is belonged from the workers in working fields. Competitiveness of manufacturing cost is getting harder because of the development of Information and telecommunication, but also globalization. Therefore, the accuracy of the assembly cost estimation is getting important. DFA and MODAPTS is useful method for measuring the working hour. But these two methods are used just as a timetable. Therefore, in this paper, we suggest the process of measuring the working hours by MODAPTS which includes the working field-s accurate information. In addition, we adduce the estimation method of accuracy assembly cost with the real information. This research could be useful for designers that can estimate the assembly cost more accurately, and also effective for the companies that which are concerned to reduce the product cost.
Abstract: The design of a steam turbine is a very complex
engineering operation that can be simplified and improved thanks to
computer-aided multi-objective optimization. This process makes use
of existing optimization algorithms and losses correlations to identify
those geometries that deliver the best balance of performance (i.e.
Pareto-optimal points).
This paper deals with a one-dimensional multi-objective and
multi-point optimization of a single-stage steam turbine. Using a
genetic optimization algorithm and an algebraic one-dimensional
ideal gas-path model based on loss and deviation correlations, a code
capable of performing the optimization of a predefined steam turbine
stage was developed. More specifically, during this study the
parameters modified (i.e. decision variables) to identify the best
performing geometries were solidity and angles both for stator and
rotor cascades, while the objective functions to maximize were totalto-
static efficiency and specific work done.
Finally, an accurate analysis of the obtained results was carried
out.
Abstract: This paper presents an application of the improved
QFD method for determining the specifications of kitchen utensils
rack. By using the improved method, the subjective nature in original
QFD was reduced; particularly in defining the relationship between
customer requirement and engineering characteristics. The regression
analysis that was used for obtaining the relationship functions
between customer requirement and engineering characteristics also
accommodated the inaccurateness of the competitive assessment
results. The improved method which is represented in the form of a
mathematical model had become a formal guidance to allocate the
resource for improving the specifications of kitchen utensils rack.
The specifications obtained had led to the achievement of the highest
feasible customer satisfaction.
Abstract: Overhead conveyor systems satisfy by their simple
construction, wide application range and their full compatibility with
other manufacturing systems, which are designed according to
international standards. Ultra-light overhead conveyor systems are
rope-based conveying systems with individually driven vehicles. The
vehicles can move automatically on the rope and this can be realized
by energy and signals. Crossings are realized by switches. Overhead
conveyor systems are particularly used in the automotive industry but
also at post offices. Overhead conveyor systems always must be
integrated with a logistical process by finding the best way for a
cheaper material flow and in order to guarantee precise and fast
workflows. With their help, any transport can take place without
wasting ground and space, without excessive company capacity, lost
or damaged products, erroneous delivery, endless travels and without
wasting time. Ultra-light overhead conveyor systems provide optimal
material flow, which produces profit and saves time. This article
illustrates the advantages of the structure of the ultra-light overhead
conveyor systems in logistics applications and explains the steps of
their system design. After an illustration of the steps, currently
available systems on the market will be shown by means of their
technical characteristics. Due to their simple construction, demands
to an ultra-light overhead conveyor system will be illustrated.
Abstract: The aim of this study was to trace the effects of growth environment on the behaviour of fattening pigs in the farm and outside it. Behavioral manifestations of pigs reared in pens with enriched environment (A lot, n: 22) were different from those of pigs reared in pens with arid environment (B lot, n: 17) in shelter and when the movement to be loaded. Pigs of B lot spent more time on the move (31%) compared to group A pigs (13%), and manifested more aggressive behavior when they were loaded. Salivary cortisol levels also showed high values for pigs in B lot after being removed from their growth environment, as compared to its concentration for A lot pigs. The enriched environment for pigs may determine different responses of behavior. Pigs raised in arid environment, were easier to loaded than pigs reared in enriched environment, but they responded to mixing and loading stress, through increases in cortisol concentrations and impaired behavioral manifestations.
Abstract: Wind turbine should be controlled to capture maximum
wind energy and to prevent the turbine from being stalled. To achieve
those two goals, wind turbine controller controls torque on generator
and limits input torque from wind by pitching blade. Usually, torque
on generator is controlled using inverter torque set point. However,
verifying a control algorithm in actual wind turbine needs a lot of
efforts to test and the actual wind turbine could be broken while testing
a control algorithm. So, several software have developed and
commercialized by Garrad Hassan, GH Bladed, and NREL, FAST.
Even though, those programs can simulate control system modeling
with subroutines or DLLs. However, those simulation programs are
not able to emulate detailed generator or PMSG. In this paper, a small
size wind turbine simulator is developed with induction motor and
small size drive train. The developed system can simulate wind turbine
control algorithm in the region before rated power.
Abstract: The Beshar River is one aquatic ecosystem,which is
affected by pollutants. This study was conducted to evaluate the
effects of human activities on the water quality of the Beshar river.
This river is approximately 190 km in length and situated at the
geographical positions of 51° 20' to 51° 48' E and 30° 18' to 30° 52'
N it is one of the most important aquatic ecosystems of Kohkiloye
and Boyerahmad province next to the city of Yasuj in southern Iran.
The Beshar river has been contaminated by industrial, agricultural
and other activities in this region such as factories, hospitals,
agricultural farms, urban surface runoff and effluent of wastewater
treatment plants. In order to evaluate the effects of these pollutants
on the quality of the Beshar river, five monitoring stations were
selected along its course. The first station is located upstream of
Yasuj near the Dehnow village; stations 2 to 4 are located east, south
and west of city; and the 5th station is located downstream of Yasuj.
Several water quality parameters were sampled. These include pH,
dissolved oxygen, biological oxygen demand (BOD), temperature,
conductivity, turbidity, total dissolved solids and discharge or flow
measurements. Water samples from the five stations were collected
and analysed to determine the following physicochemical
parameters: EC, pH, T.D.S, T.H, No2, DO, BOD5, COD during 2008
to 2009. The study shows that the BOD5 value of station 1 is at a
minimum (1.5 ppm) and increases downstream from stations 2 to 4 to
a maximum (7.2 ppm), and then decreases at station 5. The DO
values of station 1 is a maximum (9.55 ppm), decreases downstream
to stations 2 - 4 which are at a minimum (3.4 ppm), before increasing
at station 5. The amount of BOD and TDS are highest at the 4th
station and the amount of DO is lowest at this station, marking the
4th station as more highly polluted than the other stations. The
physicochemical parameters improve at the 5th station due to
pollutant degradation and dilution. Finally the point and nonpoint
pollutant sources of Beshar river were determined and compared to
the monitoring results.
Abstract: This paper proposes an analytical method for the
dynamics of generating firms- alliance networks along with business
phases. Dynamics in network developments have previously been
discussed in the research areas of organizational strategy rather than in
the areas of regional cluster, where the static properties of the
networks are often discussed. The analytical method introduces the
concept of business phases into innovation processes and uses
relationships called prior experiences; this idea was developed in
organizational strategy to investigate the state of networks from the
viewpoints of tradeoffs between link stabilization and node
exploration. This paper also discusses the results of the analytical
method using five cases of the network developments of firms. The
idea of Embeddedness helps interpret the backgrounds of the
analytical results. The analytical method is useful for policymakers of
regional clusters to establish concrete evaluation targets and a
viewpoint for comparisons of policy programs.
Abstract: In the given article the creative arts is being
investigated in the modern era and from the aspect of the artistic
interrelationship, having created by the character of his personality
and as the viewer. A study in the identity formation terms, the
definition of its being unique, unity and similarity as a global issue of
the XXI century has been conducted by the analyzing the definitions
which characterize the human nature in the arts. Spiritual universality
and human existence have been considered in the art system as a
human who is a creator, as the man hero and as the character who is
the recipient as well as the analyses which have been conducted
along with the worldwide cultural and historical processes.
Abstract: this paper gives a novel approach towards real-time speed estimation of multiple traffic vehicles using fuzzy logic and image processing techniques with proper arrangement of camera parameters. The described algorithm consists of several important steps. First, the background is estimated by computing median over time window of specific frames. Second, the foreground is extracted using fuzzy similarity approach (FSA) between estimated background pixels and the current frame pixels containing foreground and background. Third, the traffic lanes are divided into two parts for both direction vehicles for parallel processing. Finally, the speeds of vehicles are estimated by Maximum a Posterior Probability (MAP) estimator. True ground speed is determined by utilizing infrared sensors for three different vehicles and the results are compared to the proposed algorithm with an accuracy of ± 0.74 kmph.
Abstract: Homogeneous Charge Compression (HCCI) Ignition technology has been around for a long time, but has recently received renewed attention and enthusiasm. This paper deals with experimental investigations of HCCI engine using hydrous methanol as a primary fuel and Dimethyl Ether (DME) as an ignition improver. A regular diesel engine has been modified to work as HCCI engine for this investigation. The hydrous methanol is inducted and DME is injected into a single cylinder engine. Hence, hydrous methanol is used with 15% water content in HCCI engine and its performance and emission behavior is documented. The auto-ignition of Methanol is enabled by DME. The quantity of DME varies with respect to the load. In this study, the experiments are conducted independently and the effect of the hydrous methanol on the engine operating limit, heat release rate and exhaust emissions at different load conditions are investigated. The investigation also proves that the Hydrous Methanol with DME operation reduces the oxides of Nitrogen and smoke to an extreme low level which is not possible by the direct injection CI engine. Therefore, it is beneficial to use hydrous methanol-DME HCCI mode while using hydrous methanol in internal Combustion Engines.
Abstract: This paper considers the problem of scheduling maintenance actions for identical aircraft gas turbine engines. Each one of the turbines consists of parts which frequently require replacement. A finite inventory of spare parts is available and all parts are ready for replacement at any time. The inventory consists of both new and refurbished parts. Hence, these parts have different field lives. The goal is to find a replacement part sequencing that maximizes the time that the aircraft will keep functioning before the inventory is replenished. The problem is formulated as an identical parallel machine scheduling problem where the minimum completion time has to be maximized. Two models have been developed. The first one is an optimization model which is based on a 0-1 linear programming formulation, while the second one is an approximate procedure which consists in decomposing the problem into several two-machine subproblems. Each subproblem is optimally solved using the first model. Both models have been implemented using Lingo and have been tested on two sets of randomly generated data with up to 150 parts and 10 turbines. Experimental results show that the optimization model is able to solve only instances with no more than 4 turbines, while the decomposition procedure often provides near-optimal solutions within a maximum CPU time of 3 seconds.
Abstract: The aim of this work was to study the in vitro effects
of δ-lactam 1 and its 4-chlorophenyl derivative 2, on the proliferative
responses of human lymphocytes and Th1 and Th2 cytokine
secretion. The possible protective role of vitamin E on intracellular
stress oxidative induced by these compounds was also investigated.
Peripheral blood lymphocytes were isolated using differential
centrifugation on a density gradient of Histopaque. They were
cultured with mitogen concanavalin A, vitamin E (10 μM) and with
different concentrations of the compounds 1 and 2 (0.1 to 10 μM).
Proliferation (MTT assay), IL-2, INFγ and IL-4 (Elisa kits),
intracellular superoxide anion were determined. 1 and 2 were
immunostimulant and increased cytokine secretion with a shift away
from Th1 response to Th2. These properties were however
accompanied by an increase in intracellular oxidative stress. The
presence of vitamin E exhibited protective effects by reducing δ-
lactam-induced superoxide anion generation in lymphocytes.
Abstract: The purpose of this study was to investigate the effect
of combining Real Experimentation (RE) With Virtual
Experimentation (VE) on students- conceptual understanding of
photo electric effect. To achieve this, a pre–post comparison study
design was used that involved 46 undergraduate students. Two
groups were set up for this study. Participants in the control group
used RE to learn photo electric effect, whereas, participants in the
experimental group used RE in the first part of the curriculum and
VE in another part. Achievement test was given to the groups
before and after the application as pre-test and post test. The
independent samples t- test, one way Anova and Tukey HSD test
were used for testing the data obtained from the study.
According to the results of analyzes, the experimental group
was found more successful than the control group.
Abstract: In conventional reliability assessment, the reliability data of system components are treated as crisp values. The collected data have some uncertainties due to errors by human beings/machines or any other sources. These uncertainty factors will limit the understanding of system component failure due to the reason of incomplete data. In these situations, we need to generalize classical methods to fuzzy environment for studying and analyzing the systems of interest. Fuzzy set theory has been proposed to handle such vagueness by generalizing the notion of membership in a set. Essentially, in a Fuzzy Set (FS) each element is associated with a point-value selected from the unit interval [0, 1], which is termed as the grade of membership in the set. A Vague Set (VS), as well as an Intuitionistic Fuzzy Set (IFS), is a further generalization of an FS. Instead of using point-based membership as in FS, interval-based membership is used in VS. The interval-based membership in VS is more expressive in capturing vagueness of data. In the present paper, vague set theory coupled with conventional Lambda-Tau method is presented for reliability analysis of repairable systems. The methodology uses Petri nets (PN) to model the system instead of fault tree because it allows efficient simultaneous generation of minimal cuts and path sets. The presented method is illustrated with the press unit of the paper mill.
Abstract: Estimating the lifetime distribution of computer networks in which nodes and links exist in time and are bound for failure is very useful in various applications. This problem is known to be NP-hard. In this paper we present efficient combinatorial approaches to Monte Carlo estimation of network lifetime distribution. We also present some simulation results.
Abstract: Optical Character Recognition (OCR) is a very old and of great interest in pattern recognition field. In this paper we introduce a very powerful approach to recognize Persian text. We have used morphological operators, especially Hit/Miss operator to descript each sub-word and by using a template matching approach we have tried to classify generated description. We used just one font in two different sizes to verify our approach. We achieved a very good rate, up to 99.9%.
Abstract: The aim of this paper is to develop a new two dimensional time accurate Euler solver for shock tube applications. The solver was developed to study the performance of a newly built short-duration hypersonic test facility at Universiti Tenaga Nasional “UNITEN" in Malaysia. The facility has been designed, built, and commissioned for different values of diaphragm pressure ratios in order to get wide range of Mach number. The developed solver uses second order accurate cell-vertex finite volume spatial discretization and forth order accurate Runge-Kutta temporal integration and it is designed to simulate the flow process for similar driver/driven gases (e.g. air-air as working fluids). The solver is validated against analytical solution and experimental measurements in the high speed flow test facility. Further investigations were made on the flow process inside the shock tube by using the solver. The shock wave motion, reflection and interaction were investigated and their influence on the performance of the shock tube was determined. The results provide very good estimates for both shock speed and shock pressure obtained after diaphragm rupture. Also detailed information on the gasdynamic processes over the full length of the facility is available. The agreements obtained have been reasonable.