Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Minimum Height Path Partitioning of Trees
EN
A.
Bagheri
Department of Computer Engineering and IT,Amirkabir University of Technology
email@email.com
M.
Razzazi
Department of Computer Science and Engineering,Amirkabir University of Technology
iufavtzn@scientiaunknown.non
Graph partitioning is a well-known problem in the literature. In this paper, path
partitioning of trees in which the given tree is partitioned into edge-disjoint paths is considered. A linear time algorithm is given for computing a path partitioning of minimum height.
Graph partitioning,Path partitioning,Minimum height path partitioning
http://scientiairanica.sharif.edu/article_3349.html
http://scientiairanica.sharif.edu/article_3349_49e610d7ea25d75a36c5142971484cc9.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Separated Continuous Linear Programs with Fuzzy Valued Objective Function
EN
M. M.
Nasrabadi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
cdtjndhh@scientiaunknown.non
M. A.
Yaghoobi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
nkrcbdtn@scientiaunknown.non
M.
Mashinchi
Department of Mathematics and Computer Sciences,Shahid Bahonar University of Kerman
fvjdicgp@scientiaunknown.non
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 innite-dimensional linear programming problems, so-called 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.
Continuous-time linear programming,Fuzzy linear programming,Discretization,Duality
http://scientiairanica.sharif.edu/article_3350.html
http://scientiairanica.sharif.edu/article_3350_e66b1c42bcfba6b4ba6b58d0ff2b8be4.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
A New Evidential Distance Measure Based on Belief Intervals
EN
Vahid
Khatibi
Department of Computer Engineering and IT,Tarbiat Modares University
gjjtgbxd@scientiaunknown.non
G. A.
Montazer
Department of Computer Engineering and IT,Tarbiat Modares University
hfooakyh@scientiaunknown.non
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.
Evidence theory,approximate reasoning,Pattern recognition,Belief interval distance,Bacillus colony recognition,Coronary heart disease patients classication
http://scientiairanica.sharif.edu/article_3351.html
http://scientiairanica.sharif.edu/article_3351_beac8de0a860f967f8c4b915c0e873f7.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Ontological Classication of Network Denial of Service Attacks: Basis for a Unied Detection Framework
EN
B.
SADEGHIYAN
Department of Computer Engineering and IT,Amirkabir University of Technology
basadegh@ce.aut.ac.ir
A.
Varshovi
Department of Computer Engineering and IT,Amirkabir University of Technology
ali.varshovi@gmail.com
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 tree-like 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.
Availability,Denial of service,Detection framework,Ontology,Taxonomy
http://scientiairanica.sharif.edu/article_3352.html
http://scientiairanica.sharif.edu/article_3352_0eaa6662e1b7b77d5e42c6e7a0d5fc53.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Microwave Photonics Mixing
EN
B.
Cabon
Department of Electrical Engineering,Sharif University of Technology
cabon@enserg.fr
The multidisciplinary eld of Microwave-Photonics 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 up-to-date
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.
Microwave-photonics,Mixing,Wireless systems,Millimeter-wave,Ultra wide-band
http://scientiairanica.sharif.edu/article_3353.html
http://scientiairanica.sharif.edu/article_3353_34cf7e143b55d6dda89fd19555853bcd.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Simultaneous Coordinated Tuning of SSSC-Based Stabilizer and PSS Using Quadratic Mathematical Programming
EN
M. R.
Shakarami
Department of Electrical Engineering,Iran University of Science and Technology
qkrrwzso@scientiaunknown.non
A.
Kazemi
Department of Electrical Engineering,Iran University of Science and Technology
cwhtifuh@scientiaunknown.non
In a Static Synchronous Series Compensator (SSSC), a controllable AC voltage is
generated by a voltage-source converter. There are two control channels for controlling the magnitude
and phase of the voltage. When this device is used for damping inter-area oscillations in multi-machine
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 SSSC-based 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 SSSC-based stabilizer in
both control channels on damping inter-area oscillations has been assessed. Obtained results including
eigenvalue analysis and non-linear simulations, on two multi-machine 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.
Damping stabilizer,Inter-area oscillations,SSSC,PSS,Quadratic mathematic programming
http://scientiairanica.sharif.edu/article_3354.html
http://scientiairanica.sharif.edu/article_3354_27fa9785d8cd9c0557c70531cf367ef1.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
An Accurate Guidance Algorithm for Implementation Onboard Satellite Launch Vehicles
EN
Mohamadd
Marrdonny
Department of Electronical Engineering,Sharif University of Technology
btgvgwti@scientiaunknown.non
Mohammad
Mobed
Department of Electronical Engineering,Sharif University of Technology
jevrbdud@scientiaunknown.non
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 on-line state measurements is applied to compute the actual control.
The coecient matrices of the Least-Squares formula can be determined by o-line computations. The
method enjoys simplicity of implementation by onboard computers, as well as robust accuracy against
strong winds and uncertainties in thrust magnitude.
Disturbance rejection,Guidance systems,Satellites,Optimal trajectory,Launch vehicle
http://scientiairanica.sharif.edu/article_3355.html
http://scientiairanica.sharif.edu/article_3355_61a9b05ffbe2c3f3afb28c92d261f7c2.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Artificial Neural Networks Based Dynamic Weight Estimation with Optical Arrangement
EN
H.
B. Bahar
Department of Electrical Engineering,Tabriz University
carrkuwr@scientiaunknown.non
E.
safari
Department of Electrical Engineering,Tabriz University
zzbqqzbr@scientiaunknown.non
H.
A. Ghazijahani
Department of Electrical Engineering,Tabriz University
rvaxgkkc@scientiaunknown.non
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
weight-estimation 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 weight-estimation device is oscillating, by applying the weight on the scale, the
neural network by sampling the proportionate wave-shape yields the weight of object with high accuracy
and high speed.
Optical arrangement,CCD (Charged Coupled Device),RBF neural network,Dynamic weight,Measurement
http://scientiairanica.sharif.edu/article_3356.html
http://scientiairanica.sharif.edu/article_3356_73a7d5fb66eb71ef7a515032461f657c.pdf
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
17
2
2010
12
01
Modified Active Constellation Extension for PAPR Reduction of Space-Frequency Block Coded OFDM Systems
EN
M.
Ferdosizadeh Naeiny
Department of Electrical Engineering,Sharif University of Technology
ogoakaur@scientiaunknown.non
A.
Jafarnia Jahromi
Department of Electrical Engineering,Sharif University of Technology
aytlkugh@scientiaunknown.non
F.
Marvasti
Department of Electrical Engineering,Sharif University of Technology
rkzuqslt@scientiaunknown.non
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.
OFDM,PAPR,ACE,POCS,Spatial Diversity,SFBC
http://scientiairanica.sharif.edu/article_3357.html
http://scientiairanica.sharif.edu/article_3357_5d66a91164a7fcacdf34bd155f3edd18.pdf