Abstract: Prediction of viscosity of natural gas is an important parameter in the energy industries such as natural gas storage and transportation. In this study viscosity of different compositions of natural gas is modeled by using an artificial neural network (ANN) based on back-propagation method. A reliable database including more than 3841 experimental data of viscosity for testing and training of ANN is used. The designed neural network can predict the natural gas viscosity using pseudo-reduced pressure and pseudo-reduced temperature with AARD% of 0.221. The accuracy of designed ANN has been compared to other published empirical models. The comparison indicates that the proposed method can provide accurate results.
Abstract: The utilization of cheese whey as a fermentation
substrate to produce bio-ethanol is an effort to supply bio-ethanol
demand as a renewable energy. Like other process systems, modeling
is also required for fermentation process design, optimization and
plant operation. This research aims to study the fermentation process
of cheese whey by applying mathematics and fundamental concept in
chemical engineering, and to investigate the characteristic of the
cheese whey fermentation process. Steady state simulation results for
inlet substrate concentration of 50, 100 and 150 g/l, and various
values of hydraulic retention time, showed that the ethanol
productivity maximum values were 0.1091, 0.3163 and 0.5639 g/l.h
respectively. Those values were achieved at hydraulic retention time
of 20 hours, which was the minimum value used in this modeling.
This showed that operating reactor at low hydraulic retention time
was favorable. Model of bio-ethanol production from cheese whey
will enhance the understanding of what really happen in the
fermentation process.
Abstract: Discrete choice model is the most used methodology for studying traveler-s mode choice and demand. However, to calibrate the discrete choice model needs to have plenty of questionnaire survey. In this study, an aggregative model is proposed. The historical data of passenger volumes for high speed rail and domestic civil aviation are employed to calibrate and validate the model. In this study, different models are compared so as to propose the best one. From the results, systematic equations forecast better than single equation do. Models with the external variable, which is oil price, are better than models based on closed system assumption.
Abstract: This paper proposes a hybrid method for eyes localization
in facial images. The novelty is in combining techniques
that utilise colour, edge and illumination cues to improve accuracy.
The method is based on the observation that eye regions have dark
colour, high density of edges and low illumination as compared
to other parts of face. The first step in the method is to extract
connected regions from facial images using colour, edge density and
illumination cues separately. Some of the regions are then removed
by applying rules that are based on the general geometry and shape
of eyes. The remaining connected regions obtained through these
three cues are then combined in a systematic way to enhance the
identification of the candidate regions for the eyes. The geometry
and shape based rules are then applied again to further remove the
false eye regions. The proposed method was tested using images from
the PICS facial images database. The proposed method has 93.7%
and 87% accuracies for initial blobs extraction and final eye detection
respectively.
Abstract: In this paper, an accurate theoretical analysis for the achievable average channel capacity (in the Shannon sense) per user of a hybrid cellular direct-sequence/fast frequency hopping code-division multiple-access (DS/FFH-CDMA) system operating in a Rayleigh fading environment is presented. The analysis covers the downlink operation and leads to the derivation of an exact mathematical expression between the normalized average channel capacity available to each system-s user, under simultaneous optimal power and rate adaptation and the system-s parameters, as the number of hops per bit, the processing gain applied, the number of users per cell and the received signal-tonoise power ratio over the signal bandwidth. Finally, numerical results are presented to illustrate the proposed mathematical analysis.
Abstract: Roundabout work on the principle of circulation and
entry flows, where the maximum entry flow rates depend largely on
circulating flow bearing in mind that entry flows must give away to
circulating flows. Where an existing roundabout has a road hump
installed at the entry arm, it can be hypothesized that the kinematics
of vehicles may prevent the entry arm from achieving optimum
performance. Road humps are traffic calming devices placed across
road width solely as speed reduction mechanism. They are the
preferred traffic calming option in Malaysia and often used on single
and dual carriageway local routes. The speed limit on local routes is
30mph (50 km/hr). Road humps in their various forms achieved the
biggest mean speed reduction (based on a mean speed before traffic
calming of 30mph) of up to 10mph or 16 km/hr according to the UK
Department of Transport. The underlying aim of reduced speed
should be to achieve a 'safe' distribution of speeds which reflects the
function of the road and the impacts on the local community.
Constraining safe distribution of speeds may lead to poor drivers
timing and delayed reflex reaction that can probably cause accident.
Previous studies on road hump impact have focused mainly on speed
reduction, traffic volume, noise and vibrations, discomfort and delay
from the use of road humps. The paper is aimed at optimal entry and
circulating flow induced by road humps. Results show that
roundabout entry and circulating flow perform better in
circumstances where there is no road hump at entrance.
Abstract: This paper presents an investigation of the power
penalties imposed by four-wave mixing (FWM) on G.652 (Single-
Mode Fiber - SMF), G.653 (Dispersion-Shifted Fiber - DSF), and
G.655 (Non-Zero Dispersion-Shifted Fiber - NZDSF) compliant
fibers, considering the DWDM grids suggested by the ITU-T
Recommendations G.692, and G.694.1, with uniform channel
spacing of 100, 50, 25, and 12.5 GHz. The mathematical/numerical
model assumes undepleted pumping, and shows very clearly the
deleterious effect of FWM on the performance of DWDM systems,
measured by the signal-to-noise ratio (SNR). The results make it
evident that non-uniform channel spacing is practically mandatory
for WDM systems based on DSF fibers.
Abstract: One important problem in today organizations is the
existence of non-integrated information systems, inconsistency and
lack of suitable correlations between legacy and modern systems.
One main solution is to transfer the local databases into a global one.
In this regards we need to extract the data structures from the legacy
systems and integrate them with the new technology systems. In
legacy systems, huge amounts of a data are stored in legacy
databases. They require particular attention since they need more
efforts to be normalized, reformatted and moved to the modern
database environments. Designing the new integrated (global)
database architecture and applying the reverse engineering requires
data normalization. This paper proposes the use of database reverse
engineering in order to integrate legacy and modern databases in
organizations. The suggested approach consists of methods and
techniques for generating data transformation rules needed for the
data structure normalization.
Abstract: Twist drills are geometrical complex tools and thus various researchers have adopted different mathematical and experimental approaches for their simulation. The present paper acknowledges the increasing use of modern CAD systems and using the API (Application Programming Interface) of a CAD system, drilling simulations are carried out. The developed DRILL3D software routine, creates parametrically controlled tool geometries and using different cutting conditions, achieves the generation of solid models for all the relevant data involved (drilling tool, cut workpiece, undeformed chip). The final data derived, consist a platform for further direct simulations regarding the determination of cutting forces, tool wear, drilling optimizations etc.
Abstract: The dynamic behaviour of a four-bar linkage driven by a velocity controlled DC motor is discussed in the paper. In particular the author presents the results obtained by means of a specifically developed software, which implements the mathematical models of all components of the system (linkage, transmission, electric motor, control devices). The use of this software enables a more efficient design approach, since it allows the designer to check, in a simple and immediate way, the dynamic behaviour of the mechanism, arising from different values of the system parameters.
Abstract: Wavelet transform or wavelet analysis is a recently
developed mathematical tool in applied mathematics. In numerical
analysis, wavelets also serve as a Galerkin basis to solve partial
differential equations. Haar transform or Haar wavelet transform has
been used as a simplest and earliest example for orthonormal wavelet
transform. Since its popularity in wavelet analysis, there are several
definitions and various generalizations or algorithms for calculating
Haar transform. Fast Haar transform, FHT, is one of the algorithms
which can reduce the tedious calculation works in Haar transform. In
this paper, we present a modified fast and exact algorithm for FHT,
namely Modified Fast Haar Transform, MFHT. The algorithm or
procedure proposed allows certain calculation in the process
decomposition be ignored without affecting the results.
Abstract: The objective of this study was to improve our
understanding of vulnerability and environmental change; it's causes
basically show the intensity, its distribution and human-environment
effect on the ecosystem in the Apodi Valley Region, This paper is
identify, assess and classify vulnerability and environmental change
in the Apodi valley region using a combined approach of landscape
pattern and ecosystem sensitivity. Models were developed using the
following five thematic layers: Geology, geomorphology, soil,
vegetation and land use/cover, by means of a Geographical
Information Systems (GIS)-based on hydro-geophysical parameters.
In spite of the data problems and shortcomings, using ESRI-s ArcGIS
9.3 program, the vulnerability score, to classify, weight and combine
a number of 15 separate land cover classes to create a single indicator
provides a reliable measure of differences (6 classes) among regions
and communities that are exposed to similar ranges of hazards.
Indeed, the ongoing and active development of vulnerability
concepts and methods have already produced some tools to help
overcome common issues, such as acting in a context of high
uncertainties, taking into account the dynamics and spatial scale of
asocial-ecological system, or gathering viewpoints from different
sciences to combine human and impact-based approaches. Based on
this assessment, this paper proposes concrete perspectives and
possibilities to benefit from existing commonalities in the
construction and application of assessment tools.
Abstract: In this work, ionic liquids (ILs) for CO2 capturing in typical absorption/stripper process are considered. The use of ionic liquids is considered to be cost-effective because it requires less energy for solvent recovery compared to other conventional processes. A mathematical model is developed for the process based on Peng-Robinson (PR) equation of state (EoS) which is validated with experimental data for various solutions involving CO2. The model is utilized to study the sorbent and energy demand for three types of ILs at specific CO2 capturing rates. The energy demand is manifested by the vapor-liquid equilibrium temperature necessary to remove the captured CO2 from the used solvent in the regeneration step. It is found that higher recovery temperature is required for solvents with higher solubility coefficient. For all ILs, the temperature requirement is less than that required by the typical monoethanolamine (MEA) solvent. The effect of the CO2 loading in the sorbent stream on the process performance is also examined.
Abstract: We investigate the planar quasi-septic non-analytic systems which have a center-focus equilibrium at the origin and whose angular speed is constant. The system could be changed into an analytic system by two transformations, with the help of computer algebra system MATHEMATICA, the conditions of uniform isochronous center are obtained.
Abstract: Effective knowledge support relies on providing
operation-relevant knowledge to workers promptly and accurately. A
knowledge flow represents an individual-s or a group-s
knowledge-needs and referencing behavior of codified knowledge
during operation performance. The flow has been utilized to facilitate
organizational knowledge support by illustrating workers-
knowledge-needs systematically and precisely. However,
conventional knowledge-flow models cannot work well in cooperative
teams, which team members usually have diverse knowledge-needs in
terms of roles. The reason is that those models only provide one single
view to all participants and do not reflect individual knowledge-needs
in flows. Hence, we propose a role-based knowledge-flow view model
in this work. The model builds knowledge-flow views (or virtual
knowledge flows) by creating appropriate virtual knowledge nodes
and generalizing knowledge concepts to required concept levels. The
customized views could represent individual role-s knowledge-needs
in teamwork context. The novel model indicates knowledge-needs in
condensed representation from a roles perspective and enhances the
efficiency of cooperative knowledge support in organizations.
Abstract: High precision in motion is required to manipulate the
micro objects in precision industries for micro assembly, cell
manipulation etc. Precision manipulation is achieved based on the
appropriate mechanism design of micro devices such as
microgrippers. Design of a compliant based mechanism is the better
option to achieve a highly precised and controlled motion. This
research article highlights the method of designing a compliant based
three fingered microgripper suitable for holding asymmetric objects.
Topological optimization technique, a systematic method is
implemented in this research work to arrive a topologically optimized
design of the mechanism needed to perform the required micro
motion of the gripper. Optimization technique has a drawback of
generating senseless regions such as node to node connectivity and
staircase effect at the boundaries. Hence, it is required to have post
processing of the design to make it manufacturable. To reduce the
effect of post processing stage and to preserve the edges of the image,
a cubic spline interpolation technique is introduced in the MATLAB
program. Structural performance of the topologically developed
mechanism design is tested using finite element method (FEM)
software. Further the microgripper structure is examined to find its
fatigue life and vibration characteristics.
Abstract: In the present paper, active control system is used in
different heights of the building and the most effective part was
studied where the active control system is applied. The mathematical
model of the building is established in MATLAB and in order to
active control the system FLC method was used. Three different
locations of the building are chosen to apply active control system,
namely at the lowest story, the middle height of the building, and at
the highest point of the building with TMD system. The equation of
motion was written for high rise building and it was solved by statespace
method. Also passive control was used with Tuned Mass
Damper (TMD) at the top floor of the building to show the robustness
of FLC method when compared with passive control system.
Abstract: This study aimed at developing visualization tools for integrating CloudSat images and Water Vapor Satellite images. KML was used for integrating data from CloudSat Satellite and GMS-6 Water Vapor Satellite. CloudSat 2D images were transformed into 3D polygons in order to achieve 3D images. Before overlaying the images on Google Earth, GMS-6 water vapor satellite images had to be rescaled into linear images. Web service was developed using webMathematica. Shoreline from GMS-6 images was compared with shoreline from LandSat images on Google Earth for evaluation. The results showed that shoreline from GMS-6 images was highly matched with the shoreline in LandSat images from Google Earth. For CloudSat images, the visualizations were compared with GMS-6 images on Google Earth. The results showed that CloudSat and GMS-6 images were highly correlated.
Abstract: One of the main advantages of the LO paradigm is to
allow the availability of good quality, shareable learning material
through the Web. The effectiveness of the retrieval process requires a
formal description of the resources (metadata) that closely fits the
user-s search criteria; in spite of the huge international efforts in this
field, educational metadata schemata often fail to fulfil this
requirement. This work aims to improve the situation, by the
definition of a metadata model capturing specific didactic features of
shareable learning resources. It classifies LOs into “teacher-oriented"
and “student-oriented" categories, in order to describe the role a LO
is to play when it is integrated into the educational process. This
article describes the model and a first experimental validation process
that has been carried out in a controlled environment.
Abstract: Based on a non-linear single track model which
describes the dynamics of vehicle, an optimal path planning strategy
is developed. Real time optimization is used to generate reference
control values to allow leading the vehicle alongside a calculated lane
which is optimal for different objectives such as energy consumption,
run time, safety or comfort characteristics. Strict mathematic
formulation of the autonomous driving allows taking decision on
undefined situation such as lane change or obstacle avoidance. Based
on position of the vehicle, lane situation and obstacle position, the
optimization problem is reformulated in real-time to avoid the
obstacle and any car crash.