Integrity checking for aggregate queries

, Article IEEE Access ; Volume 9 , 2021 , Pages 74068-74084 ; 21693536 (ISSN) Dolatnezhad Samarin, S ; Amini, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2021

Abstract

With the advent of cloud computing and Internet of Things and delegation of data collection and aggregation to third parties, the results of the computations should be verified. In distributed models, there are multiple sources. Each source creates authenticators for the values and sends them to the aggregator. The aggregator combines the authenticated values and creates a verification object for verifying the computation/aggregation results. In this paper, we propose two constructions for verifying the results of countable and window-based countable functions. These constructions are useful for aggregate functions such as median, max/min, top-k/first-k, and range queries, where the...

Improving SQL Injection Detection Techniques

, M.Sc. Thesis Sharif University of Technology Dolatnezhad, Somayeh (Author) ; Amini, Morteza (Supervisor)

Abstract

SQL injection is one of the most important security threats in web applications with backend SQLbased database. An attacker can abuse an application’s vulnerability to change the queries sent from the application to the database. Many techniques and frameworks have been proposed for detecting and preventing SQL injection. But most of them cannot detect all types of SQL injection such as second-order attacks. In this thesis, we propose a new method to detect and prevent all types of this attack. The proposed method is a kind of anomaly-based intrusion detection methods and could be considered as a proxy between the application server and the database server. The proposed method, can detect...

Integrity Checking of Outsourced Computations with Distributed Data Sources

, Ph.D. Dissertation Sharif University of Technology Dolatnezhad, Somayeh (Author) ; Amini, Morteza (Supervisor)

Abstract

In recent years, one of the research interests is ensuring the integrity of computations done on data received from multiple data sources. Limited research has been done to ensure the integrity of computations that the output depends on data generated by different data sources. However, there are many solutions for systems that the input data is generated by a single data source. In this thesis, ensuring the integrity of multi-source aggregate functions and general functions are investigated in an untrusted server. To verify the integrity of aggregate functions, first of all, we present a construction for verifying the results of linear functions using the RSA signature. It should be noted...

All-Optical Scalable Multi-stage Interconnection Network for Data Centers

, M.Sc. Thesis Sharif University of Technology Movahederad, Mahdieh (Author) ; Koohi, Somayeh (Supervisor)

Abstract

According to the increasing amount of data exchanged among data centers, the need for speeding up and bandwidth and reduced power consumption has been increased. The information show that about 77% of the data is moved into the data centers. On the other hand, 10% of data center’s power consumption is used to data transmission. Improving the interconnection network of data centers can play an important role in reducing power consumption and speeding up. In recent years, optical interconnects have gained attention as a promising solution. Nevertheless, offering an all-optical and efficient architecture is an important issue. In this study, we intend to provide a multi-stage, all-optical...

Adopting Dynamic Topology for Energy Management in Optical Interconnection Networks in Data Centers

, M.Sc. Thesis Sharif University of Technology Rezaei, Negar (Author) ; Koohi, Somayeh (Supervisor)

Abstract

Today with the deployment of cloud computing and web applications; We need to have powerful datacenters with provisioning high bandwidth. Current data centers with electronic network interconnects, using excessive power to provisioning requisite bandwidth. Nevertheless, interconnecting networks in data centers isn’t in maximum efficiency and many components of them aren't used efficiently. So it is necessary to use an optical network with dynamic provisioning variable bandwidth and energy management. In this approach, our proposed architecture is designing topology with adopting dynamically for energy management in optical interconnect networks in data centers. To achieve this we can study...

Efficient verification of parallel matrix multiplication in public cloud: the MapReduce case

, Article Journal of Big Data ; Volume 7, Issue 1 , 2020 Bagheri, R ; Amini, M ; Dolatnezhad Samarin, S ; Sharif University of Technology

Springer Science and Business Media Deutschland GmbH 2020

Abstract

With the advent of cloud-based parallel processing techniques, services such as MapReduce have been considered by many businesses and researchers for different applications of big data computation including matrix multiplication, which has drawn much attention in recent years. However, securing the computation result integrity in such systems is an important challenge, since public clouds can be vulnerable against the misbehavior of their owners (especially for economic purposes) and external attackers. In this paper, we propose an efficient approach using Merkle tree structure to verify the computation results of matrix multiplication in MapReduce systems while enduring an acceptable...

A compiler for multi-key homomorphic signatures for Turing machines

, Article Theoretical Computer Science ; Volume 889 , 2021 , Pages 145-170 ; 03043975 (ISSN) Dolatnezhad Samarin, S ; Fiore, D ; Venturi, D ; Amini, M ; Sharif University of Technology

Elsevier B.V 2021

Abstract

At SCN 2018, Fiore and Pagnin proposed a generic compiler (called “Matrioska”) allowing to transform sufficiently expressive single-key homomorphic signatures (SKHSs) into multi-key homomorphic signatures (MKHSs) under falsifiable assumptions in the standard model. Matrioska is designed for homomorphic signatures that support programs represented as circuits. The MKHS schemes obtained through Matrioska support the evaluation and verification of arbitrary circuits over data signed from multiple users, but they require the underlying SKHS scheme to work with circuits whose size is exponential in the number of users, and thus can only support a constant number of users. In this work, we propose...

Feasibility Analysis of Backflow Detection in Lobe Blowers in Khuzestan Steel Plant using Condition Monitoring Techniques

, M.Sc. Thesis Sharif University of Technology Monazami, Ali (Author) ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)

Abstract

Lobe blowers are positive displacement machines (PDM) that are widely used in various industries. The efficiency of lobe blowers depends on the clearance between fixed and moving parts. If the clearance between the parts increases, backflow occurs, which means that the flow returns from the high-pressure zone of the outlet to the low-pressure zone of the inlet, and this makes the blower not have the initial efficiency and work with a lower capacity than its design. This research is carried out with the aim of checking the feasibility of backflow detection using two condition monitoring methods, including ultrasonic and thermography techniques. The sample of this research includes seven...

Comparison of Vibration and Ultrasonic Signal Performance in Predicting the Remaining Useful Life of Rolling Element Bearings

, M.Sc. Thesis Sharif University of Technology Yousefizadeh, Emadaddin (Author) ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)

Abstract

The prediction of Remaining Useful Life (RUL) has become a critical tool in enhancing the availability of rotating machinery. By knowing the remaining time before a bearing failure occurs during operation, significant reductions in unplanned production downtimes and associated costs can be achieved. In this study, by analyzing the time signals of vibration and ultrasonic data related to the bearing of a 4.1 MW electromotor from installation to replacement, and by investigating the behavior trends and correlation between extracted features, RMS has been ultimately identified as the health indicator in both vibration and ultrasonic techniques for monitoring the bearing’s condition. First,...

Intelligent Fault Diagnosis of Rolling Bearings under Diverse Operating Conditions with Limited Vibration Data Using Meta-Learning Algorithms

, M.Sc. Thesis Sharif University of Technology Shamsodini, Ali (Author) ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)

Abstract

Rotating machinery is a critical component in many industries, and its failure can lead to process interruptions and significant economic losses. Rolling bearings, as key elements of these machines, account for approximately 45–55% of failures. Therefore, timely detection of bearing faults plays a crucial role in reducing maintenance costs and improving safety. However, achieving timely fault detection is challenging due to weak signals and the presence of noise, which necessitates the use of advanced algorithms with strong diagnostic capabilities. Despite the considerable success of deep learning models in pattern recognition, their application to fault diagnosis of rotating machinery faces...

, M.Sc. Thesis Sharif University of Technology Seif, Mohammad Reza (Author) ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)

Abstract

Bearings play a critical role in the functionality of rotating equipment across various industries, accounting for approximately 50% of equipment failures due to bearing malfunctions. Accurate life prediction of bearings is essential not only for preventing unexpected breakdowns and subsequent damage but also for minimizing unnecessary replacements of functional bearings, which can lead to increased operational costs. With the rise of artificial intelligence, numerous predictive models have been developed; however, many of these require extensive datasets, which are often unavailable in industrial settings. Data collection is typically irregular, based on the sensitivity of the equipment,...

Identification of Possible Failures in Online Data of Gas Turbines based on Information Fusion using Artificial Intelligence

, M.Sc. Thesis Sharif University of Technology Haghighat Shoar, Amin (Author) ; Behzad, Mehdi (Supervisor) ; Mohammadi, Somayeh (Supervisor)

Abstract

Gas turbines' safe operation depends on the monitoring of performance thresholds and equipment limitations. This is accomplished through online data monitoring using sensors, with the collected data processed by monitoring software supplied by turbine manufacturers to extract information on operating conditions. The thresholds are usually set during manufacturing under standard conditions and saved in the control software. As the turbine ages and undergoes maintenance, these thresholds and operating conditions may change, requiring expert analysis to determine safe operating limits. Technological advancements have enabled the processing of operational data to establish patterns and create...

Reliability and Redundancy Analysis at a Methanol Plant in the Khark Petrochemical Complex: Investigation, Modeling, and Improvement

, M.Sc. Thesis Sharif University of Technology Modabber, Morteza (Author) ; Mohammadi, Somayeh (Supervisor) ; Saniee Monfared, Mohammad Ali (Supervisor)

Abstract

Today, reliability assessment of production systems is crucial for ensuring continuous production and minimizing operational and maintenance (O&M) costs. One way to assess reliability at the system level is to create a reliability block diagram (RBD) and estimate the failure rates of equipment over their operational periods. This approach has been utilized in this thesis, focusing on assessment of the reliability of various units within the methanol plant at Khark Petrochemical Complex. In this context, understanding the condition of the equipment criticality is essential for constructing the reliability block diagram. The Crespo model and total criticality per risk (CTR) measure have been...

The Investigation of the Effectiveness of Engine Oil Filter Particle Analysis in Enhancing the Efficiency of Diesel Engine Condition Monitoring Programs

, M.Sc. Thesis Sharif University of Technology Samaeinejad, Saman (Author) ; Behzad, Mehdi (Supervisor) ; Masoodi, Alireza (Supervisor) ; Mohammadi, Somayeh (Co-Supervisor)

Abstract

Over the years, as machines have been invented, their maintenance and repair have consistently been regarded as critical concerns. Oil analysis techniques are an effective method for monitoring the condition of mechanical equipment. Since filters in these devices continually absorb and remove a significant portion of particles from the lubricant, the selection of appropriate filters is crucial. While filters positively affect machine performance, they can also negatively impact oil condition monitoring. To mitigate this negative effect and improve the predictive accuracy of equipment health monitoring, oil filter analysis was conducted. In this research, analytical ferrography tests were...

Nanoparticle-based optical sensor arrays

, Article Nanoscale ; v. 9 , 2017 , pages 16546 – 16563 ; 2040-3364 Hormozi-Nezhad, M. R ; Bigdeli, Arafeh ; Ghasemi, Forough ; Golmohammadi, Hamed ; Abbasi-Moayed, Samira ; Farahmand Nejad, M. Amin ; Fahimi-Kashani, Nafiseh ; Jafarinejad, Somayeh ; Shahrajabian, Maryam ; Sharif University of Technology

Royal Society of Chemistry 2017

Abstract

As in many other methods that have integrated nanoparticles (NPs), the chemical nose/tongue strategy has also progressed greatly since the entrance of NPs into this field. The fascinating tunable physicochemical properties of NPs have made them powerful candidates for array-based sensing platforms and have enabled the development of real-time, sensitive and portable systems that are able to target complex mixtures of analytes. In particular, the unique optical properties of NPs have a key role in providing promising array-based sensing approaches. This review will describe the main aspects and processes of most common NP-based optical sensor arrays. The fundamental steps in the design of a...