Abstract: In order to enhance the aircraft survivability, the
infrared signatures emitted by hot engine parts should be determined
exactly. For its reduction it is necessary for the rear fuselage
temperature to be decreased. In this study, numerical modeling of flow
fields and heat transfer characteristics of an aircraft nozzle is
performed and its temperature distribution along each component wall
is predicted. The radiation shield is expected to reduce the skin
temperature of rear fuselage. The effect of material characteristic of
radiation shield on the heat transfer is also investigated. Through this
numerical analysis, design parameters related to the susceptibility of
aircraft are examined.
Abstract: This paper addresses the problem of trajectory
tracking control of an underactuated autonomous underwater vehicle
(AUV) in the horizontal plane. The underwater vehicle under
consideration is not actuated in the sway direction, and the system
matrices are not assumed to be diagonal and linear, as often found in
the literature. In addition, the effect of constant bias of environmental
disturbances is considered. Using backstepping techniques and the
tracking error dynamics, the system states are stabilized by forcing
the tracking errors to an arbitrarily small neighborhood of zero. The
effectiveness of the proposed control method is demonstrated through
numerical simulations. Simulations are carried out for an
experimental vehicle for smooth, inertial, two dimensional (2D)
reference trajectories such as constant velocity trajectory (a circle
maneuver – constant yaw rate), and time varying velocity trajectory
(a sinusoidal path – sinusoidal yaw rate).
Abstract: This work presents a comparison between the Annual
Energy Output (AEO) of two commercial vertical-axis wind turbines
(VAWTs) for a low-wind urban site: both a drag-driven and a liftdriven
concepts are examined in order to be installed on top of the
new Via dei Giustinelli building, Trieste (Italy). The power-curves,
taken from the product specification sheets, have been matched to the
wind characteristics of the selected installation site. The influence of
rotor swept area and rated power on the performance of the two
proposed wind turbines have been examined in detail, achieving a
correlation between rotor swept area, electrical generator size and
wind distribution, to be used as a guideline for the calculation of the
AEO.
Abstract: Subsonic wind tunnel experiments were conducted to
study the effect of tripped boundary layer on the pressure distribution
in the contraction region of the tunnel. Measurements were
performed by installing trip strip at two different positions in the
concave portion of the contraction. The results show that installation
of the trip strips, have significant effects on both turbulence and
pressure distribution. The reduction in the free stream turbulence and
reduction of the wall static pressure distribution deferred signified
with the location of the trip strip.
Abstract: This purpose of this paper is to present the acceptance single sampling plan when the fraction of nonconforming items is a fuzzy number and being modeled based on the fuzzy Poisson distribution. We have shown that the operating characteristic (oc) curves of the plan is like a band having a high and low bounds whose width depends on the ambiguity proportion parameter in the lot when that sample size and acceptance numbers is fixed. Finally we completed discuss opinion by a numerical example. And then we compared the oc bands of using of binomial with the oc bands of using of Poisson distribution.
Abstract: In this paper an efficient implementation of Ripemd-
160 hash function is presented. Hash functions are a special family
of cryptographic algorithms, which is used in technological
applications with requirements for security, confidentiality and
validity. Applications like PKI, IPSec, DSA, MAC-s incorporate
hash functions and are used widely today. The Ripemd-160 is
emanated from the necessity for existence of very strong algorithms
in cryptanalysis. The proposed hardware implementation can be
synthesized easily for a variety of FPGA and ASIC technologies.
Simulation results, using commercial tools, verified the efficiency of
the implementation in terms of performance and throughput. Special
care has been taken so that the proposed implementation doesn-t
introduce extra design complexity; while in parallel functionality was
kept to the required levels.
Abstract: The unique structural configuration found in human foot allows easy walking. Similar movement is hard to imitate even for an ape. It is obvious that human ambulation relates to the foot structure itself. Suppose the bones are represented as vertices and the joints as edges. This leads to the development of a special graph that represents human foot. On a footprint there are point-ofcontacts which have contact with the ground. It involves specific vertices. Theoretically, for an ideal ambulation, these points provide reactions onto the ground or the static equilibrium forces. They are arranged in sequence in form of a path. The ambulating footprint follows this path. Having the human foot graph and the path crossbred, it results in a representation that describes the profile of an ideal ambulation. This profile cites the locations where the point-of-contact experience normal reaction forces. It highlights the significant of these points.
Abstract: The aim of this study was to examine and identify the
type of Iranian financial market in terms of being symmetrical or
asymmetrical and to measure relationship between type of market
and the market's indices. In this study, daily information on the
market-s Share Price Index, Industrial Index and Top Fifty Most
Active Companies during the years 1999-2010 has been used. In
addition, to determine type of the financial market, rate of return on
Security is taken into account. In this research, by using logistic
regression analysis methods, relationship of the market type with the
above mentioned indices have been examined. The results showed
that the type of the financial market has a positive significant
association with market share price index and Industrial Index. Index
of Top Fifty Most Active Companies is significantly associated with
type of financial market, however this relationship is inverse.
Abstract: This paper provides an introduction into the
evolution of information and communication technology and illustrates its usage in the work domain. The paper is sub-divided into two parts. The first part gives an overview over the different
phases of information processing in the work domain. It starts by
charting the past and present usage of computers in work
environments and shows current technological trends, which are likely to influence future business applications. The second part
starts by briefly describing, how the usage of computers changed business processes in the past, and presents first Ambient
Intelligence applications based on identification and localization
information, which are already used in the production and retail sector. Based on current systems and prototype applications, the
paper gives an outlook of how Ambient Intelligence technologies could change business processes in the future.
Abstract: The experimental results on combustion of rice husk
in a conical fluidized bed combustor (referred to as the conical FBC)
using silica sand as the bed material are presented in this paper. The
effects of excess combustion air and combustor loading as well as the
sand bed height on the combustion pattern in FBC were investigated.
Temperatures and gas concentrations (CO and NO) along over the
combustor height as well as in the flue gas downstream from the ash
collecting cyclone were measured. The results showed that the axial
temperature profiles in FBC were explicitly affected by the
combustor loading whereas the excess air and bed height were found
to have minor influences on the temperature pattern. Meanwhile, the
combustor loading and the excess air significantly affected the axial
CO and NO concentration profiles; however, these profiles were
almost independent of the bed height. The combustion and thermal
efficiencies for this FBC were quantified for different operating
conditions.
Abstract: Grid environments consist of the volatile integration
of discrete heterogeneous resources. The notion of the Grid is to
unite different users and organisations and pool their resources into
one large computing platform where they can harness, inter-operate,
collaborate and interact. If the Grid Community is to achieve this
objective, then participants (Users and Organisations) need to be
willing to donate or share their resources and permit other
participants to use their resources. Resources do not have to be
shared at all times, since it may result in users not having access to
their own resource. The idea of reward-based computing was
developed to address the sharing problem in a pragmatic manner.
Participants are offered a reward to donate their resources to the
Grid. A reward may include monetary recompense or a pro rata share
of available resources when constrained. This latter point may imply
a quality of service, which in turn may require some globally agreed
reservation mechanism. This paper presents a platform for economybased
computing using the WebCom Grid middleware. Using this
middleware, participants can configure their resources at times and
priority levels to suit their local usage policy. The WebCom system
accounts for processing done on individual participants- resources
and rewards them accordingly.
Abstract: Friction Stir Welding is a solid state welding technique which can be used to produce sound welds between similar and dissimilar materials. Dissimilar welds which include welds between the different series of aluminium alloys, aluminium to magnesium, steel and titanium has been successfully produced by many researchers. This review covers the work conducted in the above mentioned materials and further concludes by showing the need to fully understand the FSW process in order to expand the latter industrially.
Abstract: When considering the development of constitutive
equations describing the behavior of materials under cyclic plastic
strains, different kinds of formulations can be adopted. The primary
intention of this study is to develop computer programming of
plasticity models to accurately predict the life of engineering
components. For this purpose, the energy or cyclic strain is computed
in multi-surface plasticity models in non-proportional loading and to
present their procedures and codes results.
Abstract: WikID is a wiki for industrial design engineers. An
important aspect for the viability of a wiki is the loyalty of the user
community to share their information and knowledge by adding this
knowledge to the wiki. For the initiators of a wiki it is therefore
important to use every aspect to stimulate the user community to
actively participate. In this study the focus is on the styling of the
website. The central question is: How could the WikID website be
visually designed to achieve a user experience which will incite the
user to actively participate in the WikID community? After a
literature study on the influencing factors of a website, a new
interface has been designed by applying the rules found, in order to
expand this website-s active user community. An online
questionnaire regarding the old or the new website gave insights in
the opinions of users. As expected, the new website was rated more
positively than the old website. However, the differences are limited.
Abstract: A new Feed-Forward/Feedback Generalized
Minimum Variance Pole-placement Controller to incorporate the
robustness of classical pole-placement into the flexibility of
generalized minimum variance self-tuning controller for Single-Input
Single-Output (SISO) has been proposed in this paper. The design,
which provides the user with an adaptive mechanism, which ensures
that the closed loop poles are, located at their pre-specified positions.
In addition, the controller design which has a feed-forward/feedback
structure overcomes the certain limitations existing in similar poleplacement
control designs whilst retaining the simplicity of
adaptation mechanisms used in other designs. It tracks set-point
changes with the desired speed of response, penalizes excessive
control action, and can be applied to non-minimum phase systems.
Besides, at steady state, the controller has the ability to regulate the
constant load disturbance to zero. Example simulation results using
both simulated and real plant models demonstrate the effectiveness of
the proposed controller.
Abstract: The purpose of the present work was to study the
production and process parameters optimization for the synthesis of
cellulase from Trichoderma viride in solid state fermentation (SSF)
using an agricultural wheat straw as substrates; as fungal conversion
of lignocellulosic biomass for cellulase production is one among the
major increasing demand for various biotechnological applications.
An optimization of process parameters is a necessary step to get
higher yield of product. Several kinetic parameters like pretreatment,
extraction solvent, substrate concentration, initial moisture content,
pH, incubation temperature and inoculum size were optimized for
enhanced production of third most demanded industrially important
cellulase. The maximum cellulase enzyme activity 398.10±2.43
μM/mL/min was achieved when proximally analyzed lignocellulosic
substrate wheat straw inocubated at 2% HCl as pretreatment tool
along with distilled water as extraction solvent, 3% substrate
concentration 40% moisture content with optimum pH 5.5 at 45°C
incubation temperature and 10% inoculum size.
Abstract: This study aims to determine the level of resistance of Hevea brasiliensis and Paraserianthes falcataria (synonym: Falcataria molucana) against wood rot fungi Pleurotus ostreatus based on Indonesian standard SNI 01.7207-2006 and Japanese standard JIS K 1571-2004. The variables measured were visual appearance and weight loss percentage of wood based on longitudinal and cross section fiber directions of rubber wood and sengon wood. Measurement of oven dry weight loss of wood samples performed after 12 weeks incubation. Replication performed was 10 times at each treatment combination. The results based on SNI 01.7207-2006, weight loss value of H. brasiliensis and P. falcataria wood with fiber direction longitudinal were 23,12 and 22,25% respectively and cross section were 20,77 and 18,76% respectively, and all were classified to resistance class IV (no resistance). The results based on JIS K 1571-2004, weight loss value of both woods with fiber direction cross section were 10,95 and 14,20% respectively.
Abstract: With the advent of new technologies, factors related to
mental health in e-workspaces are taken into consideration more than
ever. Studies have revealed that one of the factors affecting the
productivity of employees in an organization is occupational stress.
Another influential factor is quality of work life which is important in
the improvement of work environment conditions and organizational
efficiency. In order to uncover the quality of work life level and to
investigate the impact of occupational stress on quality of work life
among information technology employees in Iran, a cross-sectional
study design was applied and data were gathered using a
questionnaire validated by a group of experts. The results of the study
showed that information technology staffs have average level of both
occupational stress and quality of work life. Furthermore, it was
found that occupational stress has a negative impact on quality of
work life. In addition, the same results were observed for role
ambiguity, role conflict, role under-load, work-pace, work
repetitiveness and tension toward quality of work life. No significant
relation was found between role overload and quality of work life.
Finally, directions for future research are proposed and discussed.
Abstract: In this paper we are interested in classification problems
with a performance constraint on error probability. In such
problems if the constraint cannot be satisfied, then a rejection option
is introduced. For binary labelled classification, a number of SVM
based methods with rejection option have been proposed over the
past few years. All of these methods use two thresholds on the SVM
output. However, in previous works, we have shown on synthetic data
that using thresholds on the output of the optimal SVM may lead to
poor results for classification tasks with performance constraint. In
this paper a new method for supervised classification with rejection
option is proposed. It consists in two different classifiers jointly
optimized to minimize the rejection probability subject to a given
constraint on error rate. This method uses a new kernel based linear
learning machine that we have recently presented. This learning
machine is characterized by its simplicity and high training speed
which makes the simultaneous optimization of the two classifiers
computationally reasonable. The proposed classification method with
rejection option is compared to a SVM based rejection method
proposed in recent literature. Experiments show the superiority of
the proposed method.
Abstract: the effects of refining and alkaline chemicals on potential of recycling bleached chemical pulp of bagasse were investigated in this study. Recycling was done until three times. Handsheet properties such as, apparent density, light scattering coefficient, tear index, burst index, breaking length, and fold number according to TAPPI standard were measured. Water retention value also was used to considering the treatments during recycling. Refining enhanced the strength of recycled pulp by increasing fiber flexibility and swelling ability, whereas by applying chemical treatment didn't observe any improvement. The morphology of recycled fiber was considered with scanning electron microscopy (SEM).