Abstract: A new and cost effective robotic device was designed
for remote tele surgery using dual tone multi frequency technology
(DTMF). Tele system with Dual Tone Multiple Frequency has a large
capability in sending and receiving of data in hardware and software.
The robot consists of DC motors for arm movements and it is
controlled manually through a mobile phone through DTMF
Technology. The system enables the surgeon from base station to
send commands through mobile phone to the patient’s robotic system
which includes two robotic arms that translate the input into actual
instrument manipulation. A mobile phone attached to the
microcontroller 8051 which can activate robot through relays. The
Remote robot-assisted tele surgery eliminates geographic constraints
for getting surgical expertise where it is needed and allows an expert
surgeon to teach or proctor the performance of surgical technique by
real-time intervention.
Abstract: Fatigue life prediction and evaluation are the key
technologies to assure the safety and reliability of automotive rubber
components. The objective of this study is to develop the fatigue
analysis process for vulcanized rubber components, which is
applicable to predict fatigue life at initial product design step. Fatigue
life prediction methodology of vulcanized natural rubber was
proposed by incorporating the finite element analysis and fatigue
damage parameter of maximum strain appearing at the critical location
determined from fatigue test. In order to develop an appropriate
fatigue damage parameter of the rubber material, a series of
displacement controlled fatigue test was conducted using threedimensional
dumbbell specimen with different levels of mean
displacement. It was shown that the maximum strain was a proper
damage parameter, taking the mean displacement effects into account.
Nonlinear finite element analyses of three-dimensional dumbbell
specimens were performed based on a hyper-elastic material model
determined from the uni-axial tension, equi-biaxial tension and planar
test. Fatigue analysis procedure employed in this study could be used
approximately for the fatigue design.
Abstract: In this paper the problem of face recognition under variable illumination conditions is considered. Most of the works in the literature exhibit good performance under strictly controlled acquisition conditions, but the performance drastically drop when changes in pose and illumination occur, so that recently number of approaches have been proposed to deal with such variability. The aim of this work is to introduce an efficient local appearance feature extraction method based steerable pyramid (SP) for face recognition. Local information is extracted from SP sub-bands using LBP(Local binary Pattern). The underlying statistics allow us to reduce the required amount of data to be stored. The experiments carried out on different face databases confirm the effectiveness of the proposed approach.
Abstract: Effectiveness of Artificial Neural Networks (ANN)
and Support Vector Machines (SVM) classifiers for fault diagnosis of
rolling element bearings are presented in this paper. The
characteristic features of vibration signals of rotating driveline that
was run in its normal condition and with faults introduced were used
as input to ANN and SVM classifiers. Simple statistical features such
as standard deviation, skewness, kurtosis etc. of the time-domain
vibration signal segments along with peaks of the signal and peak of
power spectral density (PSD) are used as features to input the ANN
and SVM classifier. The effect of preprocessing of the vibration
signal by Discreet Wavelet Transform (DWT) prior to feature
extraction is also studied. It is shown from the experimental results
that the performance of SVM classifier in identification of bearing
condition is better then ANN and pre-processing of vibration signal
by DWT enhances the effectiveness of both ANN and SVM classifier
Abstract: In this research, Response Surface Methodology (RSM) is used to investigate the effect of four controllable input variables namely: discharge current, pulse duration, pulse off time and applied voltage Surface Roughness (SR) of on Electrical Discharge Machined surface. To study the proposed second-order polynomial model for SR, a Central Composite Design (CCD) is used to estimation the model coefficients of the four input factors, which are alleged to influence the SR in Electrical Discharge Machining (EDM) process. Experiments were conducted on AISI D2 tool steel with copper electrode. The response is modeled using RSM on experimental data. The significant coefficients are obtained by performing Analysis of Variance (ANOVA) at 5% level of significance. It is found that discharge current, pulse duration, and pulse off time and few of their interactions have significant effect on the SR. The model sufficiency is very satisfactory as the Coefficient of Determination (R2) is found to be 91.7% and adjusted R2-statistic (R2 adj ) 89.6%.
Abstract: This project relates to a two-wheeled self balancing
robot for transferring loads on different locations along a path. This
robot specifically functions as a dual mode navigation to navigate
efficiently along a desired path. First, as a plurality of distance
sensors mounted at both sides of the body for collecting information
on tilt angle of the body and second, as a plurality of speed sensors
mounted at the bottom of the body for collecting information of the
velocity of the body in relative to the ground. A microcontroller for
processing information collected from the sensors and configured to
set the path and to balance the body automatically while a processor
operatively coupled to the microcontroller and configured to compute
change of the tilt and velocity of the body. A direct current motor
operatively coupled to the microcontroller for controlling the wheels
and characterized in that a remote control is operatively coupled to
the microcontroller to operate the robot in dual navigation modes.
Abstract: A pressure-based implicit procedure to solve Navier-
Stokes equations on a nonorthogonal mesh with collocated finite
volume formulation is used to simulate flow around the smart and
conventional flaps of spoiler under the ground effect. Cantilever
beam with uniformly varying load with roller support at the free end
is considered for smart flaps. The boundedness criteria for this
procedure are determined from a Normalized Variable diagram
(NVD) scheme. The procedure incorporates es the k -ε eddyviscosity
turbulence model. The method is first validated against
experimental data. Then, the algorithm is applied for turbulent
aerodynamic flows around a spoiler section with smart and
conventional flaps for different attack angle, flap angle and ground
clearance where the results of two flaps are compared.
Abstract: In this paper, the position control of an electronic
throttle actuator is outlined. The dynamic behavior of the actuator is
described with the help of an uncertain plant model. This motivates
the controller design based on the ideas of higher-order slidingmodes.
As a consequence anti-chattering techniques can be omitted.
It is shown that the same concept is applicable to estimate unmeasureable
signals. The control law and the observer are implemented on
an electronic control unit. Results achieved by numerical simulations
and real world experiments are presented and discussed.
Abstract: Evaporator is an important and widely used heat
exchanger in air conditioning and refrigeration industries. Different
methods have been used by investigators to increase the heat transfer
rates in evaporators. One of the passive techniques to enhance heat
transfer coefficient is the application of microfin tubes. The
mechanism of heat transfer augmentation in microfin tubes is
dependent on the flow regime of two-phase flow. Therefore many
investigations of the flow patterns for in-tube evaporation have been
reported in literatures. The gravitational force, surface tension and
the vapor-liquid interfacial shear stress are known as three dominant
factors controlling the vapor and liquid distribution inside the tube. A
review of the existing literature reveals that the previous
investigations were concerned with the two-phase flow pattern for
flow boiling in horizontal tubes [12], [9]. Therefore, the objective of
the present investigation is to obtain information about the two-phase
flow patterns for evaporation of R-134a inside horizontal smooth and
microfin tubes. Also Investigation of heat transfer during flow
boiling of R-134a inside horizontal microfin and smooth tube have
been carried out experimentally The heat transfer coefficients for
annular flow in the smooth tube is shown to agree well with Gungor
and Winterton-s correlation [4]. All the flow patterns occurred in the
test can be divided into three dominant regimes, i.e., stratified-wavy
flow, wavy-annular flow and annular flow. Experimental data are
plotted in two kinds of flow maps, i.e., Weber number for the vapor
versus weber number for the liquid flow map and mass flux versus
vapor quality flow map. The transition from wavy-annular flow to
annular or stratified-wavy flow is identified in the flow maps.
Abstract: The two significant overvoltages in power system,
switching overvoltage and lightning overvoltage, are investigated in
this paper. Firstly, the effect of various power system parameters on
Line Energization overvoltages is evaluated by simulation in ATP.
The dominant parameters include line parameters; short-circuit
impedance and circuit breaker parameters. Solutions to reduce
switching overvoltages are reviewed and controlled closing using
switchsync controllers is proposed as proper method.
This paper also investigates lightning overvoltages in the
overhead-cable transition. Simulations are performed in
PSCAD/EMTDC. Surge arresters are applied in both ends of cable to
fulfill the insulation coordination. The maximum amplitude of
overvoltages inside the cable is surveyed which should be of great
concerns in insulation coordination studies.
Abstract: We propose a control design scheme that aims to
prevent undesirable liquid outpouring and suppress sloshing during
the forward and backward tilting phases of the pouring process, for
the case of liquid containers carried by manipulators. The proposed
scheme combines a partial inverse dynamics controller with a PID
controller, tuned with the use of a “metaheuristic" search algorithm.
The “metaheuristic" search algorithm tunes the PID controller based
on simulation results of the plant-s linearization around the operating
point corresponding to the critical tilting angle, where outpouring
initiates. Liquid motion is modeled using the well-known pendulumtype
model. However, the proposed controller does not require
measurements of the liquid-s motion within the tank.
Abstract: This paper maps the structure of the social network of
the 2011 class ofsixty graduate students of the Masters of Science
(Knowledge Management) programme at the Nanyang Technological
University, based on their friending relationships on Facebook. To
ensure anonymity, actual names were not used. Instead, they were
replaced with codes constructed from their gender, nationality, mode
of study, year of enrollment and a unique number. The relationships
between friends within the class, and among the seniors and alumni
of the programme wereplotted. UCINet and Pajek were used to plot
the sociogram, to compute the density, inclusivity, and degree,
global, betweenness, and Bonacich centralities, to partition the
students into two groups, namely, active and peripheral, and to
identify the cut-points. Homophily was investigated, and it was
observed for nationality and study mode. The groups students formed
on Facebook were also studied, and of fifteen groups, eight were
classified as dead, which we defined as those that have been inactive
for over two months.
Abstract: Fuzzy logic can be used when knowledge is
incomplete or when ambiguity of data exists. The purpose of
this paper is to propose a proactive fuzzy set- based model for
reacting to the risk inherent in investment activities relative to
a complete view of portfolio management. Fuzzy rules are
given where, depending on the antecedents, the portfolio size
may be slightly or significantly decreased or increased. The
decision maker considers acceptable bounds on the proportion
of acceptable risk and return. The Fuzzy Controller model
allows learning to be achieved as 1) the firing strength of each
rule is measured, 2) fuzzy output allows rules to be updated,
and 3) new actions are recommended as the system continues
to loop. An extension is given to the fuzzy controller that
evaluates potential financial loss before adjusting the
portfolio. An application is presented that illustrates the
algorithm and extension developed in the paper.
Abstract: This paper aims to select the optimal location and
setting parameters of TCSC (Thyristor Controlled Series
Compensator) controller using Particle Swarm Optimization (PSO)
and Genetic Algorithm (GA) to mitigate small signal oscillations in a
multimachine power system. Though Power System Stabilizers
(PSSs) are prime choice in this issue, installation of FACTS device
has been suggested here in order to achieve appreciable damping of
system oscillations. However, performance of any FACTS devices
highly depends upon its parameters and suitable location in the
power network. In this paper PSO as well as GA based techniques are
used separately and compared their performances to investigate this
problem. The results of small signal stability analysis have been
represented employing eigenvalue as well as time domain response in
face of two common power system disturbances e.g., varying load
and transmission line outage. It has been revealed that the PSO based
TCSC controller is more effective than GA based controller even
during critical loading condition.
Abstract: This paper focuses on a critical component of the situational awareness (SA), the neural control of depth flight of an autonomous underwater vehicle (AUV). Constant depth flight is a challenging but important task for AUVs to achieve high level of autonomy under adverse conditions. With the SA strategy, we proposed a multirate neural control of an AUV trajectory for a nontrivial mid-small size AUV “r2D4" stochastic model. This control system has been demonstrated and evaluated by simulation of diving maneuvers using software package Simulink. From the simulation results it can be seen that the chosen AUV model is stable in the presence of noises, and also can be concluded that the proposed research technique will be useful for fast SA of similar AUV systems in real-time search-and-rescue operations.
Abstract: This paper considers the control of the longitudinal
flight dynamics of an F-16 aircraft. The primary design objective
is model-following of the pitch rate q, which is the preferred
system for aircraft approach and landing. Regulation of the aircraft
velocity V (or the Mach-hold autopilot) is also considered, but
as a secondary objective. The problem is challenging because the
system is nonlinear, and also non-affine in the input. A sliding
mode controller is designed for the pitch rate, that exploits the
modal decomposition of the linearized dynamics into its short-period
and phugoid approximations. The inherent robustness of the SMC
design provides a convenient way to design controllers without gain
scheduling, with a steady-state response that is comparable to that
of a conventional polynomial based gain-scheduled approach with
integral control, but with improved transient performance. Integral
action is introduced in the sliding mode design using the recently
developed technique of “conditional integrators", and it is shown that
robust regulation is achieved with asymptotically constant exogenous
signals, without degrading the transient response. Through extensive
simulation on the nonlinear multiple-input multiple-output (MIMO)
longitudinal model of the F-16 aircraft, it is shown that the conditional
integrator design outperforms the one based on the conventional linear
control, without requiring any scheduling.
Abstract: India-s North-Eastern part, comprising of seven states, is a lowly developed, tribal population dominated region in India. Inspite of the common Mongoloid origin and lifestyle of majority of the population residing here, sharp differences exist in the status of their socio-economic development. The present paper, through a state-wise analysis, makes an attempt to find out the extent of this disparity, especially on the socio-economic front. It illustrates the situations prevailing in health, education, economic and social cohesion sector. Discussion on the implications of such disparity on social stability finds that the causes of frequent insurgency activities, that have been penetrating the region for a long time, thereby creating communal conflicts, can be traced in the economic deprivation and disparity. In the last section, the paper makes policy prescription and suggests how by taking care of disparity and deprivation both poverty and the problem of communal conflicts can be controlled.
Abstract: Considering complexity of products, new geometrical
design and investment tolerances that are necessary, measuring and
dimensional controlling involve modern and more precise methods.
Photo digitizing method using two cameras to record pictures and
utilization of conventional method named “cloud points" and data
analysis by the use of ATOUS software, is known as modern and
efficient in mentioned context. In this paper, benefits of photo
digitizing method in evaluating sampling of machining processes
have been put forward. For example, assessment of geometrical
integrity surface in 5-axis milling process and measurement of
carbide tool wear in turning process, can be can be brought forward.
Advantages of this method comparing to conventional methods have
been expressed.
Abstract: An active suspension system has been proposed to
improve the ride comfort. A quarter-car 2 degree-of-freedom (DOF)
system is designed and constructed on the basis of the concept of a
four-wheel independent suspension to simulate the actions of an
active vehicle suspension system. The purpose of a suspension
system is to support the vehicle body and increase ride comfort. The
aim of the work described in the paper was to illustrate the
application of fuzzy logic technique to the control of a continuously
damping automotive suspension system. The ride comfort is
improved by means of the reduction of the body acceleration caused
by the car body when road disturbances from smooth road and real
road roughness.
The paper describes also the model and controller used in the
study and discusses the vehicle response results obtained from a
range of road input simulations. In the conclusion, a comparison of
active suspension fuzzy control and Proportional Integration
derivative (PID) control is shown using MATLAB simulations.
Abstract: In this paper by using the port-controlled Hamiltonian
(PCH) systems theory, a full-order nonlinear controlled model is first
developed. Then a nonlinear passivity-based robust adaptive control
(PBRAC) of switched reluctance motor in the presence of external
disturbances for the purpose of torque ripple reduction and
characteristic improvement is presented. The proposed controller
design is separated into the inner loop and the outer loop controller.
In the inner loop, passivity-based control is employed by using
energy shaping techniques to produce the proper switching function.
The outer loop control is employed by robust adaptive controller to
determine the appropriate Torque command. It can also overcome the
inherent nonlinear characteristics of the system and make the whole
system robust to uncertainties and bounded disturbances. A 4KW 8/6
SRM with experimental characteristics that takes magnetic saturation
into account is modeled, simulation results show that the proposed
scheme has good performance and practical application prospects.