2010
17
2
2
0
http://scientiairanica.sharif.edu/3349.html
Minimum Height Path Partitioning of Trees
2
2
Graph partitioning is a wellknown problem in the literature. In this paper, path
partitioning of trees in which the given tree is partitioned into edgedisjoint paths is considered. A linear time algorithm is given for computing a path partitioning of minimum height.
2
Graph partitioning is a wellknown problem in the literature. In this paper, path
partitioning of trees in which the given tree is partitioned into edgedisjoint paths is considered. A linear time algorithm is given for computing a path partitioning of minimum height.
Keywords: Graph partitioning; Path partitioning; Minimum height path partitioning.
0
0


A.
Bagheri
Department of Computer Engineering and IT,Amirkabir University of Technology
Iran
email@email.com


M.
Razzazi
Department of Computer Science and Engineering,Amirkabir University of Technology
Iran
iufavtzn@scientiaunknown.non
Graph partitioning
Path partitioning
Minimum height path partitioning
http://scientiairanica.sharif.edu/3350.html
Separated Continuous Linear Programs with Fuzzy Valued Objective Function
2
2
Fuzzy linear programming problems can be used to model a wide variety of practical
applications in which all or some decision parameters are stated in an imprecise fashion. These problems
have been investigated and expanded by many researchers from various points of view. In this paper, we
study a class of innitedimensional linear programming problems, socalled separated continuous linear
programs with a fuzzy valued objective function. For this class of problem, we develop a strong duality
result and present an approximation algorithm. The basic idea is to use the discretization technique to
establish a relationship between the problem and an ordinary fuzzy linear programming problem.
2
Fuzzy linear programming problems can be used to model a wide variety of practical
applications in which all or some decision parameters are stated in an imprecise fashion. These problems
have been investigated and expanded by many researchers from various points of view. In this paper, we
study a class of innitedimensional linear programming problems, socalled separated continuous linear
programs with a fuzzy valued objective function. For this class of problem, we develop a strong duality
result and present an approximation algorithm. The basic idea is to use the discretization technique to
establish a relationship between the problem and an ordinary fuzzy linear programming problem.
Keywords: Continuoustime linear programming; Fuzzy linear programming; Discretization; Duality
0
0


M. M.
Nasrabadi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
Iran
cdtjndhh@scientiaunknown.non


M. A.
Yaghoobi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
Iran
nkrcbdtn@scientiaunknown.non


M.
Mashinchi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
Iran
fvjdicgp@scientiaunknown.non
Continuoustime linear programming
Fuzzy linear programming
Discretization
Duality
http://scientiairanica.sharif.edu/3351.html
A New Evidential Distance Measure Based on Belief Intervals
2
2
So far, most of the evidential distance and similarity measures proposed in the Dempster
Shafer theory literature have been based on the basic belief assignment function, so as the belief and
plausibility functions as two main results of the theory are not directly used in this regard. In this paper,
a new evidential distance measure is proposed based on these functions according to nearest neighborhood
concept. After assigning basic belief values to propositions and constructing the belief and plausibility
functions or the belief interval, this evidential distance measure compares the similarity between the
unknown pattern and class belief intervals. For this purpose, we rst acquire the belief and plausibility
functions or the belief intervals and then the distance between the belief intervals of uncertain pattern
feature vectors and samples are calculated. We applied this novel distance measure to the bacillus colonies
recognition and coronary heart disease patients classication problems to examine the proposed measure
capability in contrast to other evidential measures. Our experiment illustrates that the belief interval
distance measure yields the accuracy rates of 91.66 and 92.45 percent for unknown bacillus patterns
recognition and coronary heart disease patients classication, respectively, which in contrast to other
evidential measures shows superior performance.
2
So far, most of the evidential distance and similarity measures proposed in the Dempster
Shafer theory literature have been based on the basic belief assignment function, so as the belief and
plausibility functions as two main results of the theory are not directly used in this regard. In this paper,
a new evidential distance measure is proposed based on these functions according to nearest neighborhood
concept. After assigning basic belief values to propositions and constructing the belief and plausibility
functions or the belief interval, this evidential distance measure compares the similarity between the
unknown pattern and class belief intervals. For this purpose, we rst acquire the belief and plausibility
functions or the belief intervals and then the distance between the belief intervals of uncertain pattern
feature vectors and samples are calculated. We applied this novel distance measure to the bacillus colonies
recognition and coronary heart disease patients classication problems to examine the proposed measure
capability in contrast to other evidential measures. Our experiment illustrates that the belief interval
distance measure yields the accuracy rates of 91.66 and 92.45 percent for unknown bacillus patterns
recognition and coronary heart disease patients classication, respectively, which in contrast to other
evidential measures shows superior performance.
Keywords: Evidence theory; Approximate reasoning; Pattern recognition; Belief interval distance;
Bacillus colony recognition; Coronary heart disease patients classication.
0
0


Vahid
Khatibi
Department of Computer Engineering and IT,Tarbiat Modares University
Iran
gjjtgbxd@scientiaunknown.non


G. A.
Montazer
Department of Computer Engineering and IT,Tarbiat Modares University
Iran
hfooakyh@scientiaunknown.non
Evidence theory
approximate reasoning
Pattern recognition
Belief interval distance
Bacillus colony recognition
Coronary heart disease patients classication
http://scientiairanica.sharif.edu/3352.html
Ontological Classication of Network Denial of Service Attacks: Basis for a Unied Detection Framework
2
2
In this paper we introduce the notion of a detection framework to facilitate the reasoning
and cooperation process of detection and response systems. The presented framework denes four
dimensions as requirements to be satised: What to detect", Where to inspect", How to decide",
and How to alert". The rst dimension tries to unify the understanding of the problem between systems.
The second will introduce detection features and parameters. The third dimension exactly states how
intelligent systems or expert knowledge should be deployed, while the task of the fourth is to unify the
alert and message exchange format. To address the What to detect" aspect of our framework, we have
considered a network denial of service and have presented an ontology which relates three taxonomies
of DoS attacks, each from a dierent point of view: Attack Consequence, Attack Location and Attack
Scenario. For scenario based taxonomy, we present a decision treelike structure, which can be used as
a base for attack detection. All these taxonomies are then related to each other in an ontology. An
implementation of this ontology using Web Ontology Language (OWL) might help IETF's IDMEF to
construct a base for a more accurate alert correlation.
2
In this paper we introduce the notion of a detection framework to facilitate the reasoning
and cooperation process of detection and response systems. The presented framework denes four
dimensions as requirements to be satised: What to detect", Where to inspect", How to decide",
and How to alert". The rst dimension tries to unify the understanding of the problem between systems.
The second will introduce detection features and parameters. The third dimension exactly states how
intelligent systems or expert knowledge should be deployed, while the task of the fourth is to unify the
alert and message exchange format. To address the What to detect" aspect of our framework, we have
considered a network denial of service and have presented an ontology which relates three taxonomies
of DoS attacks, each from a dierent point of view: Attack Consequence, Attack Location and Attack
Scenario. For scenario based taxonomy, we present a decision treelike structure, which can be used as
a base for attack detection. All these taxonomies are then related to each other in an ontology. An
implementation of this ontology using Web Ontology Language (OWL) might help IETF's IDMEF to
construct a base for a more accurate alert correlation.
Keywords: Availability; Denial of service; Detection framework; Ontology; Taxonomy.
0
0


B.
SADEGHIYAN
Department of Computer Engineering and IT,Amirkabir University of Technology
Iran
basadegh@ce.aut.ac.ir


A.
Varshovi
Department of Computer Engineering and IT,Amirkabir University of Technology
Iran
ali.varshovi@gmail.com
Availability
Denial of service
Detection framework
Ontology
Taxonomy
http://scientiairanica.sharif.edu/3353.html
Microwave Photonics Mixing
2
2
The multidisciplinary eld of MicrowavePhotonics is at the convergence of photonic and
microwave or even wireless technologies. In this context, the processing, conversion and transmission of
microwaves, as well as high data rate digital and wireless signals, today use broadband optical techniques
with many applications. However, the frequency band available is frequently changing with uptodate
commercial standards, and it is necessary to up or down convert the frequency of the electrical signals
using a suitable optical approach for mixing. This paper intends to give an overview on the optical
techniques used for frequency conversion, i.e. mixing, and gives the advantages and drawbacks of all
techniques presented.
2
The multidisciplinary eld of MicrowavePhotonics is at the convergence of photonic and
microwave or even wireless technologies. In this context, the processing, conversion and transmission of
microwaves, as well as high data rate digital and wireless signals, today use broadband optical techniques
with many applications. However, the frequency band available is frequently changing with uptodate
commercial standards, and it is necessary to up or down convert the frequency of the electrical signals
using a suitable optical approach for mixing. This paper intends to give an overview on the optical
techniques used for frequency conversion, i.e. mixing, and gives the advantages and drawbacks of all
techniques presented.
Keywords: Microwavephotonics; Mixing; Wireless systems; Millimeterwave; Ultra wideband.
0
0


B.
Cabon
Department of Electrical Engineering,Sharif University of Technology
Iran
cabon@enserg.fr
Microwavephotonics
Mixing
Wireless systems
Millimeterwave
Ultra wideband
http://scientiairanica.sharif.edu/3354.html
Simultaneous Coordinated Tuning of SSSCBased Stabilizer and PSS Using Quadratic Mathematical Programming
2
2
In a Static Synchronous Series Compensator (SSSC), a controllable AC voltage is
generated by a voltagesource converter. There are two control channels for controlling the magnitude
and phase of the voltage. When this device is used for damping interarea oscillations in multimachine
power systems, a damping stabilizer can be included in both channels. In this paper, a method for
the simultaneous coordinated design of a Power System Stabilizer (PSS) and a SSSCbased stabilizer
is presented using quadratic mathematical programming. In this method, the gain and phase of a leadlag
stabilizer can be simultaneously calculated. By this method the eect of the SSSCbased stabilizer in
both control channels on damping interarea oscillations has been assessed. Obtained results including
eigenvalue analysis and nonlinear simulations, on two multimachine power systems under dierent
operating conditions, show that the usage of a SSSC stabilizer in a suitable control channel can signicantly
reduce the control cost of the stabilizer.
2
In a Static Synchronous Series Compensator (SSSC), a controllable AC voltage is
generated by a voltagesource converter. There are two control channels for controlling the magnitude
and phase of the voltage. When this device is used for damping interarea oscillations in multimachine
power systems, a damping stabilizer can be included in both channels. In this paper, a method for
the simultaneous coordinated design of a Power System Stabilizer (PSS) and a SSSCbased stabilizer
is presented using quadratic mathematical programming. In this method, the gain and phase of a leadlag
stabilizer can be simultaneously calculated. By this method the eect of the SSSCbased stabilizer in
both control channels on damping interarea oscillations has been assessed. Obtained results including
eigenvalue analysis and nonlinear simulations, on two multimachine power systems under dierent
operating conditions, show that the usage of a SSSC stabilizer in a suitable control channel can signicantly
reduce the control cost of the stabilizer.
Keywords: Damping stabilizer; Interarea oscillations; SSSC; PSS; Quadratic mathematic programming.
0
0


M. R.
Shakarami
Department of Electrical Engineering,Iran University of Science and Technology
Iran
qkrrwzso@scientiaunknown.non


A.
Kazemi
Department of Electrical Engineering,Iran University of Science and Technology
Iran
cwhtifuh@scientiaunknown.non
Damping stabilizer
Interarea oscillations
SSSC
PSS
Quadratic mathematic programming
http://scientiairanica.sharif.edu/3355.html
An Accurate Guidance Algorithm for Implementation Onboard Satellite Launch Vehicles
2
2
An algorithm for guiding a launch vehicle carrying a small satellite to a sun synchronous
LEO is presented. Before the launch, a nominal path and the corresponding nominal control law for
the entire journey are computed. For each sampling instant during the guided
ight, a linear equation
approximately relating the dierences between the actual and nominal values is considered, and a Least
Squares formula using data from online state measurements is applied to compute the actual control.
The coecient matrices of the LeastSquares formula can be determined by oline computations. The
method enjoys simplicity of implementation by onboard computers, as well as robust accuracy against
strong winds and uncertainties in thrust magnitude.
2
An algorithm for guiding a launch vehicle carrying a small satellite to a sun synchronous
LEO is presented. Before the launch, a nominal path and the corresponding nominal control law for
the entire journey are computed. For each sampling instant during the guided
ight, a linear equation
approximately relating the dierences between the actual and nominal values is considered, and a Least
Squares formula using data from online state measurements is applied to compute the actual control.
The coecient matrices of the LeastSquares formula can be determined by oline computations. The
method enjoys simplicity of implementation by onboard computers, as well as robust accuracy against
strong winds and uncertainties in thrust magnitude.
Keywords: Disturbance rejection; Guidance systems; Satellites; Optimal trajectory; Launch vehicle.
0
0


Mohamadd
Marrdonny
Department of Electronical Engineering,Sharif University of Technology
Iran
btgvgwti@scientiaunknown.non


Mohammad
Mobed
Department of Electronical Engineering,Sharif University of Technology
Iran
jevrbdud@scientiaunknown.non
Disturbance rejection
Guidance systems
Satellites
Optimal trajectory
Launch vehicle
http://scientiairanica.sharif.edu/3356.html
Artificial Neural Networks Based Dynamic Weight Estimation with Optical Arrangement
2
2
In this essay, an optical arrangement for the measurement of dynamic weight, by means
of conducting a thin ray of light through it, is designed in order to enhance the measuring accuracy in the
weightestimation device. In this arrangement, CCD is responsible for producing raw data for processing.
An articial neural network type, RBF, is also used to improve the quality and speed of the measurement.
While the scale of the weightestimation device is oscillating, by applying the weight on the scale, the
neural network by sampling the proportionate waveshape yields the weight of object with high accuracy
and high speed.
2
In this essay, an optical arrangement for the measurement of dynamic weight, by means
of conducting a thin ray of light through it, is designed in order to enhance the measuring accuracy in the
weightestimation device. In this arrangement, CCD is responsible for producing raw data for processing.
An articial neural network type, RBF, is also used to improve the quality and speed of the measurement.
While the scale of the weightestimation device is oscillating, by applying the weight on the scale, the
neural network by sampling the proportionate waveshape yields the weight of object with high accuracy
and high speed.
Keywords: Optical arrangement; CCD (Charged Coupled Device); RBF neural network; Dynamic
weight; Measurement.
0
0


H.
B. Bahar
Department of Electrical Engineering,Tabriz University
Iran
carrkuwr@scientiaunknown.non


E.
safari
Department of Electrical Engineering,Tabriz University
Iran
zzbqqzbr@scientiaunknown.non


H.
A. Ghazijahani
Department of Electrical Engineering,Tabriz University
Iran
rvaxgkkc@scientiaunknown.non
Optical arrangement
CCD (Charged Coupled Device)
RBF neural network
Dynamic weight
Measurement
http://scientiairanica.sharif.edu/3357.html
Modified Active Constellation Extension for PAPR Reduction of SpaceFrequency Block Coded OFDM Systems
2
2
In this paper, the Active Constellation Extension (ACE) technique is applied to Space
Frequency Block Coded (SFBC) OFDM systems to reduce the Peak to Average Power Ratio (PAPR). For
the extension of this technique to SFBC systems, it will be shown that the space frequency coded signals are
the combination of several subframes and that the ACE method may be applied to these subframes. Using
this model, an iterative ACE method, based on Projection Onto Convex Sets (POCS), is introduced. At
each iteration, the time domain samples of the subframes are clipped based on their eect on the samples
of all antennas. Then, the clipped subframes are ltered and the signals of the antennas are constructed
from the modied subframes. The simulation results show that the performance of the proposed method is
very close to the performance of the ACE method in the single antenna OFDM system.
2
In this paper, the Active Constellation Extension (ACE) technique is applied to Space
Frequency Block Coded (SFBC) OFDM systems to reduce the Peak to Average Power Ratio (PAPR). For
the extension of this technique to SFBC systems, it will be shown that the space frequency coded signals are
the combination of several subframes and that the ACE method may be applied to these subframes. Using
this model, an iterative ACE method, based on Projection Onto Convex Sets (POCS), is introduced. At
each iteration, the time domain samples of the subframes are clipped based on their eect on the samples
of all antennas. Then, the clipped subframes are ltered and the signals of the antennas are constructed
from the modied subframes. The simulation results show that the performance of the proposed method is
very close to the performance of the ACE method in the single antenna OFDM system.
Keywords: OFDM; PAPR; ACE; POCS; Spatial diversity; SFBC.
0
0


M.
Ferdosizadeh Naeiny
Department of Electrical Engineering,Sharif University of Technology
Iran
ogoakaur@scientiaunknown.non


A.
Jafarnia Jahromi
Department of Electrical Engineering,Sharif University of Technology
Iran
aytlkugh@scientiaunknown.non


F.
Marvasti
Department of Electrical Engineering,Sharif University of Technology
Iran
rkzuqslt@scientiaunknown.non
OFDM
PAPR
ACE
POCS
Spatial Diversity
SFBC