Hakem Beitollahi

• Doctor of Philosophy
• Head of hardware branch at Iran University of Science and Technology

The recognition of the same faces masked and unmasked is a paramount function in preserving consistent recognition in public security, safety, and access control. Facial recognition technologies have been seriously tested with the widespread use of masks due to infectious diseases in recent years, which cover key facial areas and reduce identificat...

In mixed‐criticality (MC) systems, tasks with varying criticality levels share resources, leading to challenges in resource management during mode transitions. Existing approaches often result in suboptimal performance due to resource contention and criticality level inheritance. This paper introduces a novel learner‐based resource management strat...

Intrusion detection in modern network environments poses significant challenges due to the increasing volume and complexity of cyber-attacks. This study proposes a hybrid approach integrating density-based clustering with deep learning to identify malicious traffic over the network. The proposed framework consists of two steps: clustering and class...

Physical Unclonable Functions (PUFs) are vulnerable to machine learning modeling attacks that can predict their responses. To counter this threat, we introduce Obfuscated PUF (OPUF), a novel PUF design that employs advanced obfuscation techniques to enhance security. OPUF significantly outperforms existing PUFs in terms of resistance to machine lea...

Recognizing the same faces with and without masks is important for ensuring consistent identification in security, access control, and public safety. This capability is crucial in scenarios like law enforcement, healthcare, and surveillance, where accurate recognition must be maintained despite facial occlusion. This research focuses on the challen...

In today's digital age, information systems (IS) are indispensable tools for organizations of all sizes. The quality of these systems, encompassing system, information, and service dimensions, significantly impacts organizational performance. This study investigates the intricate relationships between these three quality dimensions and their collec...

Most real-time systems are embedded in portable, battery-powered devices that have strict limitations on power consumption. Safety-critical embedded systems, in particular, demand a high level of reliability. To effectively enhance both reliability and power consumption, it is crucial to consider both criteria with an accurate and stable model. Exi...

In recent years, hardware sorters have been an attracted topic for researchers. Since hardware sorters play a crucial role in embedded systems, several attempts have been made to efficiently design and implement these sorters. Previous state-of-the-art hardware sorters are not suitable for embedded edge computing devices because they (1) consume hi...

Emerging cellular networks integrate diverse technologies like millimeter wave (mmWave) to deliver high capacity but face challenges like blockage sensitivity. Dual connections (DC) enhance throughput but ensuring information freshness (Age-of-Information, AoI) is crucial for real-time applications. This paper proposes a novel approach for AoI opti...

Today, vehicular communication can significantly improve traffic safety and road efficiency and as well as reduce the environmental pollution. The internet of vehicles (IoV) provides a communication platform between vehicles in intercity roads and streets of a city. Various messages such as safety messages and road traffic services can be transferr...

The proliferation of Internet of Vehicles (IoV) has revolutionized transportation systems. However, ensuring secure and privacy-preserving communication in IoV networks remains a challenge. Existing authentication protocols often compromise privacy, incur high computation costs, or are vulnerable to DDoS attacks. To address these limitations, we pr...

Convolutional Neural Network (CNN) is used in many real-world applications due to its high accuracy. The rapid growth of modern applications based on learning algorithms has increased the importance of efficient implementation of CNNs. The array-type architecture is a well-known platform for the efficient implementation of CNN models, which takes a...

In designing many systems, fault tolerance is a critical requirement for decreasing the effects of the transient faults; in this regard, a Triple Modular Redundancy (TMR) is a highlighted technique. The voter is an essential component of TMR. As the effects of the faults mask in a bit-by-bit voter, some multiple transient faults are not tolerated....

Distributed Denial of Service (DDoS) attacks are a growing threat to online services, and various methods have been developed to detect them. However, past research has mainly focused on identifying attack patterns and types, without specifically addressing the role of freely available DDoS attack tools in the escalation of these attacks. This stud...

Aging mechanisms in FPGA devices cause performance degradation and lead to lifetime reduction. Among multiple aging mechanisms, Biased-Temperature-Instability (BTI) aging mechanism is the dominant one. BTI decreases the Static-Noise-Margin (SNM) of SRAM cells leading to more Soft-Error-Rate (SER) and lower SRAMs’ stability in FPGAs. This paper prop...

Online social media (OSM) generates a massive amount of data about human behavior based on their interactions. People express their opinions, comments and share information about variety of topics of their daily life through OSM. The majority of the comments are divided into three categories: Positive, negative, and natural. Regarding the negative...

In this paper, we propose an online security-aware hardware scheduler, the so-called Secure And Fast hardware Scheduler (SAFAS), for real-time task scheduling in multi-core systems in the presence of schedule-based side-channel attacks. To avoid such attacks and ensure that all tasks meet their deadlines, SAFAS schedules critical tasks and their re...

Data uncertainty can be generated for a variety of reasons, including measurement error, sampling error, environmental monitoring, sensor networks, and medical diagnostics. The process of mining information from emerging applications such as sensors or location-based services should be handled carefully to prevent erroneous outcomes. Several heuris...

Convolutional neural networks (CNNs) are widely used in machine learning (ML) applications such as image processing. CNN requires heavy computations to provide significant accuracy for many ML tasks. Therefore, the efficient implementations of CNNs to improve performance using limited resources without accuracy reduction is a challenge for ML syste...

Reducing energy consumption under processors' temperature constraints has recently become a pressing issue in real‐time multiprocessor systems on chips (MPSoCs). The high temperature of processors affects the power and reliability of the MPSoC. Low energy consumption is necessary for real‐time embedded systems, as most of them are portable devices....

Convolutional neural networks (CNNs) have been widely deployed in artificial intelligence, including computer vision and pattern recognition. In these applications, CNN is the most computationally intensive part. Recently, many researchers have used depthwise convolution to decrease the computational load in the execution of CNNs; on the other hand...

Reliability and energy efficiency are two hostile objectives considered in designing task scheduling in most real-time multiprocessor systems on chip (MPSoC). Addressing and improving one of them may affect and degrade the efficiency of the other one and vice versa. In this paper, we intend to examine these challenges and ultimately achieve an opti...

Reliability and energy efficiency are two hostile objectives considered in designing task scheduling in most real-time multiprocessor systems on chip (MPSoC). Addressing and improving one of them may affect and degrade the efficiency of the other one and vice versa. In this paper, we intend to examine these challenges and ultimately achieve an opti...

Speech is the most common and primary mode of communication among human being. The communication between humans and machines is referred to as the human-computer interface. With the progress of technology, speech signal processing and recognition would be an important topic for many technicians and experts in different domains. Nowadays, speech pro...

Spin Transfer Torque Magnetic RAM (STT-MRAM) is one of the most promising on-chip technologies, which delivers high density, non-volatility, and near-zero leakage power. However, STT-MRAM suffers from three reliability issues, namely, read disturbance, write failure, and retention failure, that present significant challenges to its use as a reliabl...

In an application-layer distributed denial of service (App-DDoS) attack, zombie computers bring down the victim server with valid requests. Intrusion detection systems (IDS) cannot identify these requests since they have legal forms of standard TCP connections. Researchers have suggested several techniques for detecting App-DDoS traffic. There is,...

This paper proposes an efficient hardware scheduler for scheduling dependent tasks in real-time many-core systems. The main idea behind the proposed scheduler is that the operating system selects tasks that can be scheduled with the Earliest Deadline First (EDF) algorithm and groups the related tasks according to their dependency. It then transfers...

Sorting is an inseparable part of applications that process massive amounts of data. A hardware-designed sorter increases the performance at the cost of increasing the required resources, the issue that is limited in the FPGA chips. This paper proposes a new Ultra-Low-Power 3-dimensional hardware sorting architecture, the so-called ULPSorter, based...

Coarse-grained reconfigurable arrays (CGRAs) are used as low-power and high-performance accelerators in the processors of the Internet of Things (IoT) and embedded systems to accelerate the computation of intensive tasks. These accelerators speedup loops, including integer and fixed-point instructions of computation-intensive applications, in multi...

The multi-layer structure of three-dimensional Network-on-Chips (3D NoC) leads to the unequal thermal conductance between different layers and, as a result, an unbalanced thermal distribution in the chip. This issue leads to the low reliability and performance degradation of 3D NoCs. To ensure thermal safety, 3D NoCs require effective cooling metho...

Soft errors have always been a concern in the design of digital circuits. As technology down-scales toward Nanometer sizes, emergence of aging effects, process variations, and Multiple Event Transients (METs) has made the soft error rate (SER) estimation of digital circuits very challenging. This paper intends to characterize the challenges by inve...

Detecting Hardware Trojans (HTs) in digital circuits might be a challenging problem due to the stealthy nature of these malicious unwanted guests. The trigger part which is supposed to activate the Trojan under exceptional conditions, is often inserted at rare–switched nets of the design to hide them from usual verification tests mechanisms. Existi...

This paper represents an on-line time-predictable distributed hardware scheduler solution, suitable for many-core systems. We have partitioned the Main scheduler into uniform Partial schedulers to achieve a significant gain in term of performance and scalability, while software scheduling solutions impose excessive delays (in order of thousands of...

Energy consumption and elevating the chip temperature become a serious challenge in designing embedded systems mainly due to transistor scaling and integration of more components into a single chip. The temperature of the chip has significant effects on leakage current, energy consumption and reliability of the chip; hence, discovering a mechanism...

Sorting is one of the most important computational tasks in data processing applications. Recent studies show that the FPGA-based hardware accelerators are more efficient than the general-purpose processors and GPUs. By increasing the input records in the sorting network, the number of Compare-And-Swap (CAS) units would be increased, which in turn,...

(This paper is accepted in MWSCAS 2019.) Sorting is one of the most important computational tasks in data processing applications. Recent studies show that the FPGA-based hardware accelerators are more efficient than the general-purpose processors and GPUs. By increasing the input records in the sorting network, the number of Compare-And-Swap (CAS)...

This paper proposes a novel hardware-based multidimensional sorting algorithm and its respective architecture, called real-time hardware sorter (RTHS), for emerging data intensive processing applications where performance and resource conservation are serious concerns. The basic idea behind RTHS is to reduce the hardware complexity of parallel hard...

A hardware Trojan (HT) is an extra circuitry inserted into a chip design with the malicious aim of functionality alteration, reliability degradation or secret information leakage. It is normally very hard to find HT activation signals since such signals are intended to activate upon occurring very rare conditions on specific nets of the infected ci...

Ever increasing number of on-chip cores magnifies the need for efficient Network on Chip (NoC) architecture designs. To have a wide design space exploration, accurate simulators play a key role to estimate power consumption, area and temperature profile of NoCs. Access-Noxim as one of the well-known NoC simulators is used by several researchers to...

This manuscript studies and analyzes the user behavioral model of a website. Our analysis show that users have different views when encounter with a problem and structure of a website. Issues such as sociology, psychology, economics and interest to computer science products make these different views. By studying the behaviors of users, a website c...

In an application-layer distributed denial of service (DDoS) attack, zombie machines send a large number of legitimate requests to the victim server. Since these requests have legitimate formats and are sent through normal TCP connections, intrusion detection systems cannot detect them. In these attacks, an adversary does not saturate the bandwidth...

In application-layer distributed denial of service (DDoS) attacks, zombie machines attack the victim server through legitimate packets such that packets havelegitimate format and are sent through normal TCP connections. Consequently, neither intrusion detection systems (IDS) nor victim server can detects malicious packets. This paper proposes a nov...

This paper proposes a novel feedback-based control technique that tackles distributed denial of service (DDoS) attacks in four consecutive phases. While protection routers close to the server control inbound traffc rate andkeeps the server alive (phase 1), the server negotiate with upstream routers close to traffc sources to install leaky-buckets f...

This paper reviews and analyzes well-known countermeasures against distributed denial of service (DDoS) attacks. This paper provides an in-depth analysis of each countermeasure and enumerates strengths and challenges of each technique. If it is possible, the paper designs a countermeasure against each defense mechanism from the attacker’s point of...

The capability that a server can hide its location while offering various kinds of services to its clients is called hidden services or location-hiding. Almost previous low-latency anonymous communication systems such as Tor, MorphMix, etc., that can be used to implement hidden services are vulnerable against end-to-end traffic analysis attack. Thi...

Today, the Internet has become a promising platform for network-based control systems (NBCS), where packets are used to transmit feedback and control signals between a plant and controllers. On the other hand, today’s distributed denial of service (DDoS) attacks cause significant disruption to the Internet, which threaten the operation of NBCS.This...

This paper proposes a cooperative mechanism to tackle distributed denial of service (DDoS) attacks based on cooperation between the victim server and customer edge routers of the ISPs (internet service providers) that have traffic toward the victim server. The mechanism tackles the attack in three consecutive phases: first, before attack packets ca...

Overlay networks are used as proxies which mediate communication between an application and its users with-out revealing the application's location (IP address). The capability that users can communicate with an application without knowing its location is called location-hiding. Al-though recent years have provided little literature about location-...

Smart grids rely on a dependable information infrastructure for the monitoring and control applications. Two elements can enhance the suitability of the communication and control infrastructure for such smart grid applications. Overlay networks allow to resiliently deal with nodes that appear and disappear, as well as with the dynamic nature of the...

Today, overlay networks are used as a promising platform to deploy wide area of applications and services in the Internet. The application level state maintained by the overlay networks should have high degree of availability.This can be compromised when a significant percentage of overlay nodes fails simultaneously (massive failure). The first pro...

Distributed intelligence and secure interconnected communication networks constitute recognized key factors for the economic operation of electricity infrastructures in competitive power markets. Hence, electric power utilities need to extend risk management frameworks with adequate tools for assessing consequences of ICT (information and communica...

Filtering techniques are one of the main approaches to protect applications from Denial of Service Attacks (DoS). However filtering techniques suffer from two main chal- lenges: a) the accuracy detection of DoS traffic and b) pro- cessing time. Fosel (Filtering with the help of an Overlay Security Layer) has been proposed to protect application sit...

Today, peer-to-peer (P2P) systems are used as a promising platform to deploy new applications and services in the internet. There are much interest in emerging P2P overlay network because they provide a good substrate for creating large scale data sharing, content distribution and application-level multicast applications. Overlay networks also have...

In the last few years, P2P systems have rapidly evolved and emerged as a promising platform to deploy new applications and services in the Internet. The main reasons for this is that P2P systems are self-organizing, have a decentralized nature, good scalability, efficient query search, and good resilience in the presence of node failures. However m...

Overlay networks enable applications to communicate with users without disclosing their IP addresses; hence overlay networks are used to protect applications against DoS attacks by hiding an applicationpsilas location. This paper analyzes three popular overlay networks (Chord, CAN, and Pastry) by simulation to answer to this question: which topolog...

The paper presents a set of control system scenarios implemented in two testbeds developed in the context of the European Project CRUTIAL - CRitical UTility InfrastructurAL Resilience. The selected scenarios refer to power control systems encompassing information and communication security of SCADA systems for grid teleoperation, impact of attacks...

Control systems for electrical microgrids rely ever more on heterogeneous off-the-shelf technology for hardware, software and networking among the intelligent electronic devices that are associated with dispersed energy resources. For distributed microgrid applications in a dynamic environment, overlay networks provide an opportunity for a flexible...

Denial of service (DoS) attacks are major threat against availability in the Internet. A large number of countermeasure techniques try to detect attack and then filter out DoS attack packets. Unfortunately these techniques that filter DoS traffic by looking at known attack patterns or statistical anomalies in the traffic patterns can be defeated by...

Today Internet is becoming an emerging technology for remote control of industrial applications, where one site needs to control another site remotely (e.g. power plants controllers). Denial-of-Service (DoS) attacks may cause significant disruptions to the Internet which will threaten the operation of such network based control systems. Overlay net...

Various smart power grid applications can be based on agent control systems such as intelligent protection, agents in power market, supply demand matching, autonomous electricity grid (AEG), etc. The dynamic nature of these applications makes that the information infrastructure un-derlying the power grid is needed not only for static con-figuration...

Today distributed industrial networks use Internet to transmit feedback and control signals between a plant and a controller. However there are several attacks on the Internet. From these attacks perhaps denial-of-service (DoS) attack is the most detrimen-tal one that affects the packet delivery. DoS attack causes significant disruption to the Inte...

The general approach to fault tolerance in uniprocessor systems is to maintain enough time redundancy in the schedule so that any task instance can be re-executed in presence of faults during the execution. In this paper a scheme is presented to add enough and efficient time redundancy to the Earliest-Deadline-First (EDF) scheduling policy for peri...

The general approach to fault tolerance in uniprocessor systems is to use time redundancy in the schedule so that any task instance can be re-executed in presence of faults during the execution. In this paper a scheme is presented to add enough and efficient time redundancy to the rate-monotonic (RM) scheduling policy for periodic real-time tasks....

In order to improve and deploy distributed control systems for the power grid a robust ICT infrastructure is required partially based on dependable middleware that exploits redundancy and diversity in communication networks. The dynamic nature of power grid applications makes necessity of using peer-to-peer (P2P) networks in this system. The main r...

In the last few years, P2P systems have rapidly evolved and emerged as a promising platform to deploy new applications and services in the internet. The main reasons for this is that P2P systems are self-organize, having decentralized nature, good scalability, having efficient query search, good resilience in the presence of node failures. However...

This paper presents the performance analysis of several well-known partitioning scheduling algorithms in real-time and fault-tolerant multiprocessor systems. Both static and dynamic scheduling algorithms are analyzed. Partitioning scheduling algorithms, which are studied here, are heuristic algorithms that are formed by combining any of the bin-pac...

Control systems for electrical microgrids rely ever more on an information infrastructure, consisting of heterogeneous off-the-shelf communication technology for hardware, software and networking. This provides flexibility for the application as new services become possible, but also implies vulnerabilities as the correct execution of microgrid con...