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fault-location
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A Technique for Program Fault Location Using External Information Sources
, M.Sc. Thesis Sharif University of Technology ; Mirian Hossein Abadi, Hassan (Supervisor) ; Habibi, Jafar (Co-Advisor)
Abstract
In recent years, there have been many studies aimed at finding program defect using information of previous ones. These studies, by using the program text, previous bugs, and information related to version control and project management systems create an defect prediction model to find other defect prone areas in the program. The output of defect prediction methods is part of the program’s text, which is likely to have defects. Considering that the result of this method is just the text of the program and does not provide any extra information for finding defects to the user, these methods have not yet been applied to the software industry. On the other hand, by spreading the use of Q & A...
Optimal placement of sectionalizing switch considering switch malfunction probability
, Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 403-413 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Sectionalizing switches (SSs) are often presumed to function fully reliable. However, SSs are exposed to have some malfunctions, whereby undermining their ability to improve service reliability. This paper presents a model to integrate SS malfunction probability into SS placement problem. The model aims to minimize the total SSs costs as well as customers interruption cost. The proposed model is formulated in mixed integer programing, which can be easily solved via several available solvers and gain global optimal solution. The proposed model indicates the extent to which the placement problem is affected by uncertainty associated with SSs functionality, and how not considering SSs...
Optimal placement of sectionalizing switch considering switch malfunction probability
, Article IEEE Transactions on Smart Grid ; Volume 10, Issue 1 , 2019 , Pages 403-413 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Safdarian, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Sectionalizing switches (SSs) are often presumed to function fully reliable. However, SSs are exposed to have some malfunctions, whereby undermining their ability to improve service reliability. This paper presents a model to integrate SS malfunction probability into SS placement problem. The model aims to minimize the total SSs costs as well as customers interruption cost. The proposed model is formulated in mixed integer programing, which can be easily solved via several available solvers and gain global optimal solution. The proposed model indicates the extent to which the placement problem is affected by uncertainty associated with SSs functionality, and how not considering SSs...
Open-Circuit Fault Detection and Localization in Five-Level Active Neutral Point Clamped Converter
, M.Sc. Thesis Sharif University of Technology ; Zolghadri, Mohammad Reza (Supervisor)
Abstract
Five-Level Active-Neutral-Point -Clamped (5L-ANPC) converter is used for medium-voltage and high-power applications. In many of these applications, availability and robustness against fault are the most important issues. On the other hand, this converter is made of a large number of power semiconductor switches, diodes and capacitors which could increase the failure probability. Thus, fault detection of power circuit elements is necessary for fault tolerant operation of the converter. In this thesis, following an introduction to the topology and operation principles of Five-Level Active Neutral point clamped converter, a novel open-circuit fault detection and localization method is...
Design of an Optimal Multi Agent System for Decentralized Implementation of the Active Distribution Management System's Functions Using State Estimation
, Ph.D. Dissertation Sharif University of Technology ; Abbaspour Tehrani Fard, Ali (Supervisor) ; Moeini Aghtaie, Moein (Co-Supervisor)
Abstract
In recent years, due to the increase in distributed generation, the use of renewable energy sources and the emergence of restructuring and energy markets, traditional distribution networks transform to complex and active distribution networks. These issues, along with requirements such as increasing power quality and reliability, have increased the need to provide active distribution management systems and the use of effective network monitoring, control and protection systems. Due to the complexity and expanse of distribution networks, as well as the development of the use of metering elements and remotely controllable elements, one of the important issues in these systems is the...
Limiting fault currents in wind power plants using superconductive shielded core reactors
, Article IEEE Power and Energy Society 2008 General Meeting: Conversion and Delivery of Electrical Energy in the 21st Century, PES, Pittsburgh, PA, 20 July 2008 through 24 July 2008 ; 2008 ; 9781424419067 (ISBN) ; Salehfar, H ; Varahram, H ; Sharif University of Technology
2008
Abstract
In this paper we investigate the effects of superconducting shielded core reactor (SSCR) on the operation of induction generators. Large number of induction generators used in wind power plants generally increase the short circuit current level of the system. The reason is that they provide parallel reduced-impedance paths for the fault currents. Taking advantage of SSCR in wind power plants allows for using these generating units in large numbers with no concerns about the system fault current increments. The study is performed on a test system using the conventional model of an induction generator and a new effective model for SSCR based on its shielding behavior. Mathematical equations...
Secure steganography using Gabor filter and neural networks
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 4920 LNCS , 2008 , Pages 33-49 ; 03029743 (ISSN); 3540690166 (ISBN); 9783540690160 (ISBN) ; Zahedi Kermani, Z ; Sharif University of Technology
2008
Abstract
The main concern of steganography (image hiding) methods is to embed a secret image into a host image in such a way that it causes minimum distortion to the host; to make it possible to extract a version of secret image from the host in such a way that the extracted version of secret image be as similar as possible to its original version (this should be possible even after usual attacks on the host image), and to provide ways of embedding secret images with larger size into a given host image. In this paper we propose a method that covers all above mentioned concerns by suggesting the idea of finding from an image data base, the most suitable host for a given secret image. In our method,...
Reliability enhancement in switching substations using fault current limiters
, Article 2006 9th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS, Stockholm, 11 June 2006 through 15 June 2006 ; 2006 ; 9171783520 (ISBN); 9789171783523 (ISBN) ; Fotuhi Firuzabad, M ; Sidhu, T. S ; Sharif University of Technology
2006
Abstract
Power system equipments are normally designed for a specific system and load situation. This situation could change significantly as a result of the system expansion or aging. Among the system equipments, circuit breakers are more sensitive to the system expansion and they must be able to isolate the faulty components if a fault occurs. As the system load increases in the future, the power network must be expanded. In this situation, either the switching equipments must be replaced in order to be able to respond to the new fault current or the fault current must be limited to the interrupting capability of the existing circuit breakers. Application of Fault current Limiters (FCL) serves as a...