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Developing inherently resilient software against soft-errors based on algorithm level inherent features
, Article Journal of Electronic Testing: Theory and Applications (JETTA) ; Vol. 30, issue. 2 , 2014 , p. 193-212 ; Miremadi, S. G ; Rahmani, A. M ; Sharif University of Technology
Abstract
A potential peculiarity of software systems is that a large number of soft-errors are inherently derated (masked) at the software level. The rate of error-deration may depend on the type of algorithms and data structures used in the software. This paper investigates the effects of the underlying algorithms of programs on the rate of error-deration. Eight different benchmark programs were used in the study; each of them was implemented by four different algorithms, i.e. divide-and-conquer, dynamic, backtracking and branch-and-bound. About 10,000 errors were injected into each program in order to quantify and analyze the error-derating capabilities of different algorithm-designing- techniques....
Derating of distribution transformers under non-linear loads using a combined analytical-finite elements approach
, Article IET Electric Power Applications ; Volume 10, Issue 8 , 2016 , Pages 779-787 ; 17518660 (ISSN) ; Faiz, J ; Oraee, H ; Sharif University of Technology
Institution of Engineering and Technology
Abstract
Supplying non-linear loads causes increased losses in transformers which eventually leads to their reduced life spans. Therefore, transformers are derated in order to protect them against premature loss of life. To do this, load losses including ohmic loss and winding eddy current (WEC) loss need to be estimated. This study suggests an improved analytical approach using finite element method (FEM) which includes all material characteristics and geometrical structures in order to calculate WEC loss under non-sinusoidal load current in each winding individually. By adopting this procedure, harmonic loss factor as a dominant parameter in transformers derating is estimated. By emphasising the...
A new definition for total harmonic distortion in inverter-fed induction motors including loss considerations
, Article 42nd International Conference on Large High Voltage Electric Systems 2008, CIGRE 2008, Paris, 24 August 2008 through 29 August 2008 ; 2008 ; Kaboli, S ; Oraee, H ; Sharif University of Technology
2008
Abstract
Harmonic information is necessary tools in the estimation of motors life and performance. The conventional expression of harmonic amount is carried out by total Harmonic distortion. This distortion factor is only related to amplitude of harmonics while the motor loss is affected by frequency domain of them. In this paper a new definition of this factor has been presented. This definition includes the frequency of harmonics as well as their amplitudes. Experimental results verify the validity of this new definition
Analysis of Distribution Transformer Derating Under Non-Linear Loads
, M.Sc. Thesis Sharif University of Technology ; Oraee Mirzamani, Hashem (Supervisor) ; Feyz, Javad (Co-Advisor)
Abstract
Transformer is one of the most important equipments in power systems which its reliable performance plays a vital role in increasing of power system's reliability regarding to its importance. Traditionally, designers of transformer consider transformer's parameter under "Usual Service Conditions" but the challenge which has been brought up in contrast to this approach in recent years, is wide applications of non-linear loads in different levels of power systems, especially in its distribution level. Use of non-linear loads leads to flow of non-sinusoidal load current. Hence, Power Quality indexes have been distorted in power systems. Passing non-sinusoidal load current through transformer...
Investigation of Group Pile Behavior under Lateral Loads in Clayey Soils
,
M.Sc. Thesis
Sharif University of Technology
;
Pak, Ali
(Supervisor)
Abstract
Piles are usually used in groups. The complicated interaction between piles on the one hand and between piles and their surrounding soil on the other hand, have made it difficult to recognize mechanisms that influence the pile group behavior and analyze it accurately. In this research, three dimensional models in ABAQUS software were used to investigate response of single piles and pile groups under lateral loading in clayey soils. Configuration of piles in a group, connection of piles to the pile cap, pile spacings, and pile cross section were taken into consideration as some important factors affecting response of pile groups. All the modeled piles were categorized as long piles. In order...
Using genetic algorithm to identify soft-error derating blocks of an application program
, Article Proceedings - 15th Euromicro Conference on Digital System Design, DSD 2012, 5 September 2012 through 8 September 2012 ; September , 2012 , Pages 359-367 ; 9780769547985 (ISBN) ; Rahmani, A. M ; Mansoor, A ; Miremadi, S. G ; Sharif University of Technology
2012
Abstract
Soft-errors are increasingly considered as a major cause for computer system failures. Software techniques are used as cost-effective and flexible techniques to tolerate soft-errors but the introduced overhead is not acceptable in some safety-critical real-time systems. The identification of the program blocks and protecting only vulnerable blocks against soft-errors reduces the performance overhead. In this paper, we present a genetic algorithm to identify the vulnerable program blocks as well as the derating program blocks against soft-errors. Then, only vulnerable blocks are protected by some software-based soft-error tolerance techniques to achieve a lower performance and space overhead....
Efficient algorithms to accurately compute derating factors of digital circuits
, Article Microelectronics Reliability ; Volume 52, Issue 6 , June , 2012 , Pages 1215-1226 ; 00262714 (ISSN) ; Tahoori, M. B ; Fazeli, M ; Miremadi, S. G ; Sharif University of Technology
2012
Abstract
Fast, accurate, and detailed Soft Error Rate (SER) estimation of digital circuits is essential for cost-efficient reliable design. A major step to accurately estimate a circuit SER is the computation of failure probability, which requires the computation of three derating factors, namely logical, electrical, and timing derating. The unified treatment of these derating factors is crucial to obtain accurate failure probability. Existing SER estimation techniques are either unscalable to large circuits or inaccurate due to lack of unified treatment of all derating factors. In this paper, we present fast and efficient algorithms to estimate SERs of circuit components in the presence of single...