Abstract: In order to compare the performance of the carbon dioxide and HFC-125 heat pumps for medium-and high-temperature heating, both heat pump cycles were optimized using a simulation method. To fairly compare the performance of the cycles by using different working fluids, each cycle was optimized from the viewpoint of heating COP by two design parameters. The first is the gas cooler exit temperature and the other is the ratio of the overall heat conductance of the gas cooler to the combined overall heat conductance of the gas cooler and the evaporator. The inlet and outlet temperatures of secondary fluid of the gas cooler were fixed at 40/90°C and 40/150°C.The results shows that the HFC-125 heat pump has 6% higher heating COP than carbon dioxide heat pump when the heat sink exit temperature is fixed at 90ºC, while the latter outperforms the former when the heat sink exit temperature is fixed at 150ºC under the simulation conditions considered in the present study.
Abstract: This paper puts forward one kind of air-fuel ratio
control method with PI controller. With the help of
MATLAB/SIMULINK software, the mathematical model of air-fuel
ratio control system for distributorless CNG engine is constructed.
The objective is to maintain cylinder-to-cylinder air-fuel ratio at a
prescribed set point, determined primarily by the state of the Three-
Way-Catalyst (TWC), so that the pollutants in the exhaust are
removed with the highest efficiency. The concurrent control of airfuel
under transient conditions could be implemented by Proportional
and Integral (PI) controller. The simulation result indicates that the
control methods can easily eliminate the air/fuel maldistribution and
maintain the air/fuel ratio at the stochiometry within minimum
engine events.
Abstract: The objective of this paper is to a design of pattern
classification model based on the back-propagation (BP) algorithm for
decision support system. Standard BP model has done full connection
of each node in the layers from input to output layers. Therefore, it
takes a lot of computing time and iteration computing for good
performance and less accepted error rate when we are doing some
pattern generation or training the network.
However, this model is using exclusive connection in between
hidden layer nodes and output nodes. The advantage of this model is
less number of iteration and better performance compare with standard
back-propagation model. We simulated some cases of classification
data and different setting of network factors (e.g. hidden layer number
and nodes, number of classification and iteration). During our
simulation, we found that most of simulations cases were satisfied by
BP based using exclusive connection network model compared to
standard BP. We expect that this algorithm can be available to
identification of user face, analysis of data, mapping data in between
environment data and information.
Abstract: Atmospheric stability plays the most important role in
the transport and dispersion of air pollutants. Different methods are
used for stability determination with varying degrees of complexity.
Most of these methods are based on the relative magnitude of
convective and mechanical turbulence in atmospheric motions.
Richardson number, Monin-Obukhov length, Pasquill-Gifford
stability classification and Pasquill–Turner stability classification, are
the most common parameters and methods. The Pasquill–Turner
Method (PTM), which is employed in this study, makes use of
observations of wind speed, insolation and the time of day to classify
atmospheric stability with distinguishable indices. In this study, a
model is presented to determination of atmospheric stability
conditions using PTM. As a case study, meteorological data of
Mehrabad station in Tehran from 2000 to 2005 is applied to model.
Here, three different categories are considered to deduce the pattern
of stability conditions. First, the total pattern of stability classification
is obtained and results show that atmosphere is 38.77%, 27.26%,
33.97%, at stable, neutral and unstable condition, respectively. It is
also observed that days are mostly unstable (66.50%) while nights are
mostly stable (72.55%). Second, monthly and seasonal patterns are
derived and results indicate that relative frequency of stable
conditions decrease during January to June and increase during June
to December, while results for unstable conditions are exactly in
opposite manner. Autumn is the most stable season with relative
frequency of 50.69% for stable condition, whilst, it is 42.79%,
34.38% and 27.08% for winter, summer and spring, respectively.
Hourly stability pattern is the third category that points out that
unstable condition is dominant from approximately 03-15 GTM and
04-12 GTM for warm and cold seasons, respectively. Finally,
correlation between atmospheric stability and CO concentration is
achieved.
Abstract: In this study, a system of encryption based on chaotic
sequences is described. The system is used for encrypting digital
image data for the purpose of secure image transmission. An image
secure communication scheme based on Logistic map chaotic
sequences with a nonlinear function is proposed in this paper.
Encryption and decryption keys are obtained by one-dimensional
Logistic map that generates secret key for the input of the nonlinear
function. Receiver can recover the information using the received
signal and identical key sequences through the inverse system
technique. The results of computer simulations indicate that the
transmitted source image can be correctly and reliably recovered by
using proposed scheme even under the noisy channel. The
performance of the system will be discussed through evaluating the
quality of recovered image with and without channel noise.
Abstract: This experiment discusses the effects of fracture
parameters such as depth, length, width, angle and the number of the
fracture to the conductance properties of laterite using the DUK-2B
digital electrical measurement system combined with the method of
simulating the fractures. The results of experiment show that the
changes of fracture parameters produce effects to the conductance
properties of laterite. There is a clear degressive period of the
conductivity of laterite during increasing the depth, length, width, or
the angle and the quantity of fracture gradually. When the depth of
fracture exceeds the half thickness of the soil body, the conductivity of
laterite shows evidently non-linear diminishing pattern and the
amplitude of decrease tends to increase. The length of fracture has
fewer effects than the depth to the conductivity. When the width of
fracture reaches some fixed values, the change of the conductivity is
less sensitive to the change of the width, and at this time, the
conductivity of laterite maintains at a stable level. When the angle of
fracture is less than 45°, the decrease of the conductivity is more
clearly as the angle increases. But when angle is more than 45°,
change of the conductivity is relatively gentle as the angle increases.
The increasing quantity of the fracture causes the other fracture
parameters having great impact on the change of conductivity. When
moisture content and temperature were unchanged, depth and angle of
fractures are the major factors affecting the conductivity of laterite
soil; quantity, length, and width are minor influencing factors. The
sensitivity of fracture parameters affect conductivity of laterite soil is:
depth >angles >quantity >length >width.
Abstract: Optical character recognition of cursive scripts
presents a number of challenging problems in both segmentation and
recognition processes in different languages, including Persian. In
order to overcome these problems, we use a newly developed Persian
word segmentation method and a recognition-based segmentation
technique to overcome its segmentation problems. This method is
robust as well as flexible. It also increases the system-s tolerances to
font variations. The implementation results of this method on a
comprehensive database show a high degree of accuracy which meets
the requirements for commercial use. Extended with a suitable pre
and post-processing, the method offers a simple and fast framework
to develop a full OCR system.
Abstract: In this paper we present a photo mosaic smartphone
application in client-server based large-scale image databases. Photo
mosaic is not a new concept, but there are very few smartphone
applications especially for a huge number of images in the
client-server environment. To support large-scale image databases,
we first propose an overall framework working as a client-server
model. We then present a concept of image-PAA features to efficiently
handle a huge number of images and discuss its lower bounding
property. We also present a best-match algorithm that exploits the
lower bounding property of image-PAA. We finally implement an
efficient Android-based application and demonstrate its feasibility.
Abstract: Next generation wireless/mobile networks will be IP based cellular networks integrating the internet with cellular networks. In this paper, we propose a new architecture for a high speed transport system and a mobile management protocol for mobile internet users in a transport system. Existing mobility management protocols (MIPv6, HMIPv6) do not consider real world fast moving wireless hosts (e.g. passengers in a train). For this reason, we define a virtual organization (VO) and proposed the VO architecture for the transport system. We also classify mobility as VO mobility (intra VO) and macro mobility (inter VO). Handoffs in VO are locally managed and transparent to the CH while macro mobility is managed with Mobile IPv6. And, from the features of the transport system, such as fixed route and steady speed, we deduce the movement route and the handoff disruption time of each handoff. To reduce packet loss during handoff disruption time, we propose pre-registration scheme using pre-registration. Moreover, the proposed protocol can eliminate unnecessary binding updates resulting from sequence movement at high speed. The performance evaluations demonstrate our proposed protocol has a good performance at transport system environment. Our proposed protocol can be applied to the usage of wireless internet on the train, subway, and high speed train.
Abstract: This paper presents anapproach of hybridizing two or more artificial intelligence (AI) techniques which arebeing used to
fuzzify the workstress level ranking and categorize the rating accordingly. The use of two or more techniques (hybrid approach)
has been considered in this case, as combining different techniques may lead to neutralizing each other-s weaknesses generating a
superior hybrid solution. Recent researches have shown that there is a
need for a more valid and reliable tools, for assessing work stress. Thus artificial intelligence techniques have been applied in this
instance to provide a solution to a psychological application. An overview about the novel and autonomous interactive model for analysing work-stress that has been developedusing multi-agent
systems is also presented in this paper. The establishment of the intelligent multi-agent decision analyser (IMADA) using hybridized technique of neural networks and fuzzy logic within the multi-agent based framework is also described.
Abstract: With the approaching of digital era, various interactive
service platforms and systems support human beings- needs in lives by
different contents and measures. Design strategies have gradually
turned from function-based to user-oriented, and are often customized.
In other words, how designers include users- value reaction in creation
becomes the goal. Creative design service of interior design requires
positive interaction and communication to allow users to obtain full
design information, recognize the style and process of personal needs,
develop creative service design, lower communication time and cost
and satisfy users- sense of achievement. Thus, by constructing a
co-design method, based on the communication between interior
designers and users, this study recognizes users- real needs and
provides the measure of co-design for designers and users.
Abstract: In the current Grid environment, efficient workload
management presents a significant challenge, for which there are
exorbitant de facto standards encompassing resource discovery,
brokerage, and data transfer, among others. In addition, the real-time
resource status, essential for an optimal resource allocation strategy,
is often not readily accessible. To address these issues and provide a
cleaner abstraction of the Grid with the potential of generalizing into
arbitrary resource-sharing environment, this paper proposes a new
Condor-based pilot mechanism applied in the PanDA architecture,
PanDA-PF WMS, with the goal of providing a more generic yet
efficient resource allocating strategy. In this architecture, the PanDA
server primarily acts as a repository of user jobs, responding to pilot
requests from distributed, remote resources. Scheduling decisions are
subsequently made according to the real-time resource information
reported by pilots. Pilot Factory is a Condor-inspired solution for a
scalable pilot dissemination and effectively functions as a resource
provisioning mechanism through which the user-job server, PanDA,
reaches out to the candidate resources only on demand.
Abstract: Scarcity of water resources and huge costs of
establishing new hydraulic installations necessitate optimal
exploitation from existing reservoirs. Sustainable management and
efficient exploitation from existing finite water resources are
important factors in water resource management, particularly in the
periods of water insufficiency and in dry regions, and on account of
competitive allocations in the view of exploitation management. This
study aims to minimize reservoir water release from a determined
rate of demand. A numerical model for water optimal exploitation
has been developed using GAMS introduced by the World Bank and
applied to the case of Meijaran dam, northern Iran. The results
indicate that this model can optimize the function of reservoir
exploitation while required water for lower parts of the region will be
supplied. Further, allocating optimal water from reservoir, the
optimal rate of water allocated to any group of the users were
specified to increase benefits in curve dam exploitation.
Abstract: Fatigue behaviors of Lead Zirconate Titanate (PZT)
ceramics under different amplitude of bipolar electrical loads have
been investigated. Fatigue behavior is represented by the change of
hysteresis loops and remnant polarization. Three levels of electrical
load amplitudes (1.00, 1.25 and 1.50 kV /mm) were applied in this
experimental. It was found that the remnant polarization decreased
significantly with the number of loading cycles. The degree of fatigue
degradation depends on the amplitude of electric field. The higher
amplitude exhibits the greater fatigue degradation.
Abstract: This study examines the inelastic behavior of adjacent planar reinforced concrete (R.C.) frames subjected to strong ground motions. The investigation focuses on the effects of vertical ground motion on the seismic pounding. The examined structures are modeled and analyzed by RUAUMOKO dynamic nonlinear analysis program using reliable hysteretic models for both structural members and contact elements. It is found that the vertical ground motion mildly affects the seismic response of adjacent buildings subjected to structural pounding and, for this reason, it can be ignored from the displacement and interstorey drifts assessment. However, the structural damage is moderately affected by the vertical component of earthquakes.
Abstract: The purpose of this study was to investigate relationships between satisfaction with major and career decision efficacy and career attitude maturity of engineering college students by performing correlation analysis. Gender differences in between satisfaction with major and career decision efficacy and career attitude maturity were also examined by T-test. The results T-test revealed gender differences in only career decision efficacy. Male Students scored significantly higher than did female students on career decision efficacy and satisfaction with major. The results of correlation analysis showed a) satisfaction with major were significantly associated with career decision efficacy, b) satisfaction with major were significantly associated with career attitude maturity, and c) career decision efficacy were significantly associated with career attitude maturity. As a result,we found the importance of satisfaction in engineering college students- major studies when deciding their career.
Abstract: Benefits to the organisation are just as important as technical ability when it comes to software success. The challenge is to provide industry with professionals who understand this. In other words: How to teach computer engineering students to look beyond technology, and at the benefits of software to organizations? This paper reports on the conceptual design of a section of the computer networks module aimed to sensitize the students to the organisational context.
Checkland focuses on different worldviews represented by various role players in the organisation. He developed the Soft Systems Methodology that guides purposeful action in organisations, while incorporating different worldviews in the modeling process. If we can sensitize students to these methods, they are likely to appreciate the wider context of application of system software. This paper will provide literature on these concepts as well as detail on how the students will be guided to adopt these concepts.
Abstract: In this research, a biofiltration process to remove
ammonia gas from gas stream using agricultural residue biofilter
medias is studied. The experiments were conducted in laboratoryscale
biofilter. The biofilter medias were a mixture of manure
fertilizer and bagasse at various ratios i.e., 1:3, 1:5 and 1:7. The
experiments were performed for a period of 40 days. The empty bed
retention time (EBRT) is 78s. The moisture content of biofilter media
was maintained at 45-60% using water. The results showed that the
agricultural residues (manure fertilizer and bagasse) are suitable as
biofilter media for ammonia gas removal in biofiltration process.
The maximum efficiency of ammonia gas removal is observed
from the 1:5 of manure fertilizer: bagasse ratio at 89.93%. The
biofiltration is more effective at low ammonia gas concentration. In
addition, the mixture ratio of biofilter media is not a significant factor
in biofiltration operation while the most significant factor for
biofiltration operation is the inlet ammonia gas concentration.
Abstract: This article presents a current-mode universal biquadratic filter. The proposed circuit can apparently provide standard functions of the biquad filter: low-pass, high-pass, bandpass, band-reject and all-pass functions. The circuit uses 4 current controlled transconductance amplifiers (CCTAs) and 2 grounded capacitors. In addition, the pole frequency and quality factor can be adjusted by electronic method by adjusting the bias currents of the CCTA. The proposed circuit uses only grounded capacitors without additional external resistors, the proposed circuit is considerably appropriate to further developing into an integrated circuit. The results of PSPICE simulation program are corresponding to the theoretical analysis.
Abstract: Bond Graph as a unified multidisciplinary tool is widely
used not only for dynamic modelling but also for Fault Detection and
Isolation because of its structural and causal proprieties. A binary
Fault Signature Matrix is systematically generated but to make the
final binary decision is not always feasible because of the problems
revealed by such method. The purpose of this paper is introducing a
methodology for the improvement of the classical binary method of
decision-making, so that the unknown and identical failure signatures
can be treated to improve the robustness. This approach consists of
associating the evaluated residuals and the components reliability data
to build a Hybrid Bayesian Network. This network is used in two
distinct inference procedures: one for the continuous part and the
other for the discrete part. The continuous nodes of the network are
the prior probabilities of the components failures, which are used by
the inference procedure on the discrete part to compute the posterior
probabilities of the failures. The developed methodology is applied
to a real steam generator pilot process.