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computing-systems
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Membership Service in a Distributed High Performance Virtual Computing System
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
Today with the development of te?nology, human ?allenges and problems have become even more complicated. In a way that as time went by the need for higher processing power to solve these problems has increased. High performance computers, are a category of computers whi? are used to solve su? problems. In the last two decade, distributed systems have become the most common way of gaining high performance. Here, Virtualization, an old te?nology whi? has revived in the last decade, providing spectacular features like isolation, migration, ease of management and creating opportunities like virtual clusters has proved to facilitate distributed processing. With the improvement of virtualizer’s...
Construction of a Framework for the Realization of Neuro-Fuzzy Computing Structures Based on the Physical Behavior of Processing Elements
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
In this thesis we concentrated on the application of memristor-rossbars for the hardware implementation of neuro-fuzzy systems. At first we showed that using memristive devices for this purpose has several problems and demonstrated the availability of the positive feedback in the behavior of this passive element. Then, by proposing new learning structure we tried to overcome some of these drawbacks. In the rest of this thesis we focused on the hardware implementation of neuro-fuzzy systems based on memristor crossbar structures. At first, hardware implementation of the Active Learning Method (ALM) is presented.
Next, new learning and computing method is proposed by creating and using...
Next, new learning and computing method is proposed by creating and using...
Performance Improvement of Machine Learning based Intrusion Detection Systems
, M.Sc. Thesis Sharif University of Technology ; Jafari Siavoshani, Mahdi (Supervisor)
Abstract
The rapid growth of computer networks has increased the importance of analytics and traffic analysis tools for these networks, and the increasing importance of these networks has increased the importance of security of these networks and the intrusion detection in these networks. Many studies aimed at providing a powerful way to quickly and accurately detect computer network intrusions, each of which has addressed this issue.The common point of all these methods is their reliance on the features extracted from network traffic by an expert. This strong dependence has prevented these methods from being flexible against new attacks and methods of intrusion or changes in the current normal...
Optimizing Load Balancing for Serverless Computing Platforms Using Modeling Approaches
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
Serverless Computing is a new framework for cloud computing. In this framework the service provider will take the responsibility of scaling applications by assigning adequate computational resources and instantiating multiple instances on their data-centers. The service provider dynamically allocate the resources to the application in real-time. In this manner it can reduce on data center costs and increase resource utilization. In this thesis, we propose an approach for creating performance evaluation models for serverless platforms. The model can predict the performance properties of different applications under various workload conditions. The performance model is based on queueing theory...
A fast two-level Speaker Identification method employing sparse representation and GMM-based methods
, Article 2012 11th International Conference on Information Science, Signal Processing and their Applications, ISSPA 2012 ; 2012 , Pages 45-48 ; 9781467303828 (ISBN) ; Sameti, H ; Khaki, H ; Babaali, B ; Sharif University of Technology
2012
Abstract
In large population Speaker Identification (SI), computation time has become one of the most important issues in recent real time systems. Test computation time depends on the cost of likelihood computation between test features and registered speaker models. For real time application of speaker identification, system must identify an unknown speaker quickly. Hence the conventional SI methods cannot be used. In this paper, we propose a two-step method that utilizes two different identification methods. In the first step we use Nearest Neighbor method to decrease the search space. In the second step we use GMM-based SI methods to specify the target speaker. We achieved 3.5× speed-ups without...
Feature-based content dissemination process in opportunistic networks
, Article 26th IEEE Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, PIMRC 2015, 30 August 2015 through 2 September 2015 ; Volume 2015-December , 2015 , Pages 1464-1469 ; 9781467367820 (ISBN) ; Elhami, G ; Pakravan, M. R ; Sharif University of Technology
Abstract
In order to respond to drastically increased traffic demands in mobile networks such as cellulars, opportunistic communication has been introduced as a data offloading strategy. Delivering the contents using peer-to-peer data dissemination is more preferable compared to epidemic diffusion schemes. To implement peer-to-peer dissemination, one needs to define the peer selection and content dissemination policies. Efficient content dissemination relies on the selection of suitable peers. Besides that, the peers require to choose what contents to be transmitted between them. In this paper, we propose multi-level master/slave peer selection algorithm (MMSA) and variance-based multi-metric chunk...
Neural network prediction model of three-phase fluids flow in heterogeneous porous media using scaling analysis
, Article Journal of Petroleum Science and Engineering ; Volume 138 , 2016 , Pages 122-137 ; 09204105 (ISSN) ; Alizadeh, M ; Rafiee, J ; Moshirfarahi, M. M ; Sharif University of Technology
Elsevier
Abstract
Scaling analysis of fluid displacement in porous media is a reliable, fast method to evaluate the displacement performance of different oil production processes under various conditions. This paper presents the scaling studies of multiphase fluid flow through permeable media with a special attention to the three-phase immiscible water alternating gas (WAG) flooding under conditions prevailing in many oil reservoirs. The investigations are performed on a heterogeneous reservoir to study in detail the sensitivity of the displacement process to the scaling groups using various combinations of the process controlling parameters. The procedure of Inspectional analysis (IA) was utilized to...
On the modal incremental dynamic analysis of reinforced concrete structures, using a trilinear idealization model
, Article Engineering Structures ; Volume 33, Issue 4 , 2011 , Pages 1117-1122 ; 01410296 (ISSN) ; Mofid, M ; Sharif University of Technology
Abstract
In order to estimate the seismic demands at the performance level, the inelastic behavior of concrete structures should be considered. Incremental dynamic analysis (IDA) based on a nonlinear response time history analysis (NL-RHA) is considered to be the most accurate method in seismic demand calculations. However, modal incremental dynamic analysis (MIDA), based on the equivalent single-degree-of-freedom (SDF) oscillator, is also often used in studying structural engineering performances. As the MIDA method has usually not been applied to reinforced concrete (RC) structures, in this study an attempt is made to investigate the performances of RC frames and to compare the results obtained...
Evaluation of modal incremental dynamic analysis, using input energy intensity and modified bilinear curve
, Article Structural Design of Tall and Special Buildings ; Volume 18, Issue 5 , 2009 , Pages 573-586 ; 15417794 (ISSN) ; Mofid, M ; Sharif University of Technology
2009
Abstract
In this paper, a technique for the study of nonlinear performance of structures in different levels of earthquakes is developed. In this method, the Incremental Dynamic Analysis (IDA) curves are not achieved from nonlinear dynamic analysis of multi-degree-of-freedom (MDF) structure. However, the procedure of constructing these curves is based on modelling of the entire structure with several single-degrees-of-freedom (SDF) structures and evaluating them through the modal pushover analysis method. An innovative idea for approximating pushover curves that is based on error distribution is introduced in this investigation. Furthermore, the total input energy applied towards the SDF oscillator,...
An experimental investigation of the effect of fracture dip angle on oil recovery and drainage rate in free fall gravity drainage in fractured reservoirs using a glass micromodel (A pore level investigation)
, Article Petroleum Science and Technology ; Volume 31, Issue 4 , 2013 , Pages 355-367 ; 10916466 (ISSN) ; Kharrat, R ; Ghazanfari, M ; Sharif University of Technology
2013
Abstract
Gravity drainage is the main production mechanism in the gas invaded zone in naturally fractured reservoirs. However, there are large ambiguities and complexities, resulting from the dynamic of oil depletion from matrix blocks toward the fracture network. Visualization of drained oil at pore scale using glass micromodels provides the opportunity to better understand the effects of different parameters which might affect oil recovery from fractured reservoirs. In this work a micromodel apparatus generated by laser etching is used to perform some gravity drainage tests on the network patterns. The experiments were performed on double block systems using crude oil. The block to block...
Fault injection into verilog models for dependability evaluation of digital systems
, Article Proceedings - 2nd International Symposium on Parallel and Distributed Computing, ISPDC 2003, 13 October 2003 through 14 October 2003 ; October , 2015 , Pages 281-287 ; 0769520693 (ISBN) ; 9780769520698 (ISBN) ; Miremadi, S. G ; Ejlali, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper presents transient and permanent fault injection into Verilog models of digital systems during the design phase by a developed simulation-based fault injection tool called INJECT. With this fault injection tool, it is possible to inject crucial fault models in all abstraction levels (such as swith-level) supported by Verilog HDL. Several fault models for injecting into Verilog models are specified and described. Analyzing the results obtained from the fault injections, using INJECT enables system designers to inform from dependable parameters, such as fault latency, propagation and coverage. As a case study, a 32-bit processor, namely DP32, has been evaluated and effects of faults...
A fault-tolerant cache architecture based on binary set partitioning
, Article Microelectronics Reliability ; Volume 46, Issue 1 , 2006 , Pages 86-99 ; 00262714 (ISSN) ; Miremadi, S. G ; Sharif University of Technology
2006
Abstract
Caches, which are comprised much of a CPU chip area and transistor counts, are reasonable targets for transient single and multiple faults induced from energetic particles. This paper presents: (1) a new fault detection scheme for tag arrays of cache memories and (2) an architectural cache to improve performance as well as dependability. In this architecture, cache space is divided into sets of different sizes and different tag lengths. Using the proposed fault detection scheme, i.e., GParity, when single and multiple errors are detected in a word, the word is rewritten by its correct data from memory and its GParity code is recomputed. The error detection scheme and the cache architecture...
Soft error mitigation in cache memories of embedded systems by means of a protected scheme
, Article 2nd Latin-American Symposium on Dependable Computing, LADC 2005, Salvador, 25 October 2005 through 28 October 2005 ; Volume 3747 LNCS , 2005 , Pages 121-130 ; 03029743 (ISSN); 3540295720 (ISBN); 9783540295723 (ISBN) ; Miremadi, S. G ; Sharif University of Technology
2005
Abstract
The size and speed of SRAM caches of embedded systems are increasing in response to demands for higher performance. However, the SRAM caches are vulnerable to soft errors originated from energetic nuclear particles or electrical sources. This paper proposes a new protected cache scheme, which provides high performance as well as high fault detection coverage. In this scheme, the cache space is divided into sets of different sizes. Here, the length of tag fields associated to each set is unique and is different from the other sets. The other remained bits of tags are used for protecting the tag using a fault detection scheme e.g., generalized parity. This leads to protect the cache without...
Fault injection into verilog models for dependability evaluation of digital systems
, Article 2nd International Symposium on Parallel and Distributed Computing, ISPDC 2003, 13 October 2003 through 14 October 2003 ; 2003 , Pages 281-287 ; 0769520693 (ISBN); 9780769520698 (ISBN) ; Miremadi, S. G ; Ejlali, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2003
Abstract
This paper presents transient and permanent fault injection into Verilog models of digital systems during the design phase by a developed simulation-based fault injection tool called INJECT. With this fault injection tool, it is possible to inject crucial fault models in all abstraction levels (such as swith-level) supported by Verilog HDL. Several fault models for injecting into Verilog models are specified and described. Analyzing the results obtained from the fault injections, using INJECT enables system designers to inform from dependable parameters, such as fault latency, propagation and coverage. As a case study, a 32-bit processor, namely DP32, has been evaluated and effects of faults...
Using description logics for network vulnerability analysis
, Article International Conference on Networking, International Conference on Systems and International Conference on Mobile Communications and Learning Technologies, ICN/ICONS/MCL'06, Morne, 23 April 2006 through 29 April 2006 ; Volume 2006 , 2006 ; 0769525520 (ISBN); 9780769525525 (ISBN) ; Jalili, R ; Abolhassani, H ; Shahriari, H. R ; Sharif University of Technology
2006
Abstract
The distributed nature and complexity of computer networks and various services provided via them, makes the networks vulnerable to numerous attacks. The TCP/IP presumptions which are based on using this protocol to provide a simple, open communication infrastructure in an academic and collaborative environment, causes this protocol lack of built-in mechanisms for authentication, integrity and privacy. Even though in the last few years a more systematic approach to TCP/IP network security problem has been followed, a formal approach to this problem is lacking. In this paper, we propose using Description Logics as a formal model which could be used to analyze TCP/IP networks against attacks....
Collaborative privacy management in P2P online social networks
, Article 12th International ISC Conference on Information Security and Cryptology, 8 September 2015 through 10 September 2015 ; 2015 , Pages 64-72 ; 9781467376099 (ISBN) ; Alizadeh, M ; Abbas Pour, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
Online Social Networks (OSNs) have become widely popular in recent years. In spite of users' interest to join OSNs, sharing vast amounts of personal information and resources in these networks might result in privacy issues for them. In the centralized OSNs, access control policies defined by users are enforced by OSN providers. Moreover, as these shared resources are stored by providers, they can access them. To avoid such problems, various architectures for decentralized OSNs are proposed. But the proposed architectures for P2P OSNs yet do not support any mechanism for collaborative privacy management on the shared content. By increasing the amount of resources such as photos which is...
Straggler mitigation in distributed matrix multiplication: fundamental limits and optimal coding
, Article IEEE Transactions on Information Theory ; Volume 66, Issue 3 , 2020 , Pages 1920-1933 ; Maddah Ali, M. A ; Avestimehr, A. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
We consider the problem of massive matrix multiplication, which underlies many data analytic applications, in a large-scale distributed system comprising a group of worker nodes. We target the stragglers' delay performance bottleneck, which is due to the unpredictable latency in waiting for slowest nodes (or stragglers) to finish their tasks. We propose a novel coding strategy, named entangled polynomial code, for designing the intermediate computations at the worker nodes in order to minimize the recovery threshold (i.e., the number of workers that we need to wait for in order to compute the final output). We demonstrate the optimality of entangled polynomial code in several cases, and show...
A secure attribute based keyword search scheme against keyword guessing attack
, Article 2016 8th International Symposium on Telecommunications, IST 2016,17 March 2017 ; 2017 , Pages 124-128 ; 9781509034345 (ISBN) ; Ameri, M. H ; Mohajeri, J ; Eghlidos, T ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
To provide the privacy of the users who receive some computing services from the cloud, the users must encrypt their documents before outsourcing them to the cloud. Computation on outsourced encrypted data in the cloud rises some complexity to the system specially in the case when an entity would like to find some documents related to a special keyword. Searchable encryption is a tool for data owners to encrypt their data in a searchable manner. Generally, there exist two kinds of searchable encryption, namely symmetric (secret key) and asymmetric (public key) ones. Most of the public key searchable encryption schemes are vulnerable to the keyword guessing attack (KGA). In this paper we...
A scalable dependability scheme for routing fabric of SRAM-based reconfigurable devices
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 23, Issue 9 , August , 2015 , Pages 1868-1878 ; 10638210 (ISSN) ; Asadi, H ; Khaleghi, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
With the continual scaling of feature size, system failure due to soft errors is getting more frequent in CMOS technology. Soft errors have particularly severe effects in static random-access memory (SRAM)-based reconfigurable devices (SRDs) since an error in SRD configuration bits can permanently change the functionality of the system. Since interconnect resources are the dominant contributor to the overall configuration memory upsets in SRD-based designs, the system failure rate can be significantly reduced by mitigating soft errors in routing fabric. This paper first presents a comprehensive analysis of SRD switch box susceptibility to short and open faults. Based on this analysis, we...
Passive primary/backup-based scheduling for simultaneous power and reliability management on heterogeneous embedded systems
, Article IEEE Transactions on Sustainable Computing ; 2022 , Pages 1-12 ; 23773782 (ISSN) ; Siyadatzadeh, R ; Ansari, M ; Ejlali, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In addition to meeting the real-time constraint, power/energy efficiency and high reliability are two vital objectives for real-time embedded systems. Recently, heterogeneous multicore systems have been considered an appropriate solution for achieving joint power/energy efficiency and high reliability. However, power/energy and reliability are two conflict requirements due to the inherent redundancy of fault-tolerance techniques. Also, because of the heterogeneity of the system, the execution of the tasks, especially real-time tasks, in the heterogeneous system is more complicated than the homogeneous system. The proposed method in this paper employs a passive primary/backup technique to...