Sotiris Ioannidis

Sotiris Ioannidis
Technical University of Crete | TUC · Department of Electronic and Computer Engineering

Doctor of Philosophy

About

271
Publications
85,009
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5,881
Citations

Publications

Publications (271)
Article
Full-text available
Intensive care unit (ICU) patients with venous thromboembolism (VTE) and/or cancer suffer from high mortality rates. Mortality prediction in the ICU has been a major medical challenge for which several scoring systems exist but lack in specificity. This study focuses on two target groups, namely patients with thrombosis or cancer. The main goal is...
Preprint
Full-text available
Traditional signature-based intrusion detection systems inspect packet headers and payloads to report any malicious or abnormal traffic behavior that is observed in the network. With the advent and rapid adoption of network encryption mechanisms, typical deep packet inspection systems that monitor network packet payload contents are becoming less e...
Article
Despite the tremendous socioeconomic importance of supply chains (SCs), security officers and operators are faced with no easy and integrated way for protecting their critical, and interconnected, infrastructures from cyber-attacks. As a result, solutions and methodologies that support the detection of malicious activity on SCs are constantly resea...
Preprint
Full-text available
Modern Internet of Things (IoT) environments are monitored via a large number of IoT enabled sensing devices, with the data acquisition and processing infrastructure setting restrictions in terms of computational power and energy resources. To alleviate this issue, sensors are often configured to operate at relatively low sampling frequencies, yiel...
Article
This study introduces a novel, reproducible and reusable Twitter bot identification system. The system uses a machine learning (ML) pipeline, fed with hundreds of features extracted from a Twitter corpus. The main objective of the proposed ML pipeline is to train and validate different state-of-the-art machine learning models, where the eXtreme Gra...
Article
Full-text available
Online social networks (OSN) are used by millions of users, daily. This user-base shares and discovers different opinions on popular topics. The social influence of large groups may be affected by user beliefs or be attracted by the interest in particular news or products. A large number of users, gathered in a single group or number of followers,...
Article
Modern commodity computing systems are composed by a number of different heterogeneous processing units, each of which has its own unique performance and energy characteristics. However, the majority of current network packet processing frameworks targets only a specific processing unit (either the CPU or accelerator), leaving the remaining computa...
Preprint
Full-text available
On 24 February 2022, Russia invaded Ukraine, also known now as Russo-Ukrainian War. We have initiated an ongoing dataset acquisition from Twitter API. Until the day this paper was written the dataset has reached the amount of 57.3 million tweets, originating from 7.7 million users. We apply an initial volume and sentiment analysis, while the datase...
Chapter
A large number of EU organisations already leverage Big Data pools to drive value and investments. This trend also applies to the banking sector. As a specific example, CaixaBank currently manages more than 300 different data sources (more than 4 PetaBytes of data and increasing), and more than 700 internal and external active users and services ar...
Article
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The adoption of Internet of Things (IoT) devices, applications and services gradually transform our everyday lives. In parallel, the transition from linear to circular economic (CE) models provide an even more fertile ground for novel types of services, and the update and enrichment of legacy ones. To fully realize the potential of the interplay be...
Preprint
Full-text available
Modern commodity computing systems are composed by a number of different heterogeneous processing units, each of which has its own unique performance and energy characteristics. However, the majority of current network packet processing frameworks targets only a specific processing unit (either the CPU or accelerator), leaving the remaining computa...
Chapter
Manufacturing processes are highly complex. Production lines have several robots and digital tools, generating massive amounts of data. Unstructured, noisy and incomplete data have to be collected, aggregated, pre-processed and transformed into structured messages of a common, unified format in order to be analysed not only for the monitoring of th...
Preprint
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Twitter is one of the most popular social networks attracting millions of users, while a considerable proportion of online discourse is captured. It provides a simple usage framework with short messages and an efficient application programming interface (API) enabling the research community to study and analyze several aspects of this social networ...
Conference Paper
The Android OS is currently used in a plethora of devices that play a core part of our everyday life, such as mobile phones, tablets, smart home appliances, entertainment systems and embedded devices. The majority of these devices typically process and store a vast amount of security-critical and privacy-sensitive data, including personal contacts,...
Article
This article studies the prospects of combining two promising wireless technologies for 6G wireless systems, namely ambient backscatter communications and Programmable Wireless Environments (PWEs). Ambient backscattering carries the promise of battery-less and perpetually operating IoT devices that "surf" ambient electromagnetic waves rather than g...
Article
Full-text available
Eco-friendly systems are necessitated nowadays, as the global consumption is increasing. A data-driven aspect is prominent, involving the Internet of Things (IoT) as the main enabler of a Circular Economy (CE). Henceforth, IoT equipment records the system’s functionality, with machine learning (ML) optimizing green computing operations. Entities ex...
Article
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Exerting cyber-control over any natural resource and process has seen explosive growth, yielding technological breakthroughs in recent years. This impressive growth has so far stemmed from a horizontal expansion of control across application sectors, such as industrial, business, and household task automations. This article proposes cyber-control v...
Conference Paper
Emerging technologies are facilitating our daily activities and drive the digital transformation. The Internet of Things (IoT) and 5G communications will provide a wide range of new applications and business opportunities, but with a wide and quite complex attack surface. Several users are not aware of the underlying threats and most of them do not...
Article
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The adoption of network traffic encryption is continually growing. Popular applications use encryption protocols to secure communications and protect the privacy of users. In addition, a large portion of malware is spread through the network traffic taking advantage of encryption protocols to hide its presence and activity. Entering into the era of...
Article
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Digital technologies are facilitating our daily activities, and thus leading to the social transformation with the upcoming 5G communications and the Internet of Things. However, mainstream and sophisticated attacks are remaining a threat, both for individuals and organisations. Cyber Range emerges as a promising solution to effectively train peopl...
Article
Full-text available
Structured approaches to the definition of service orchestrations facilitate the composition of components and services and allow for more capable and powerful applications, while introducing many advantages such as service reusability, cost reduction, and simplification of organization alliances. A variety of such approaches exist in the literatur...
Article
Phylogenetics study the evolutionary history of organisms using an iterative process of creating and evaluating phylogenetic trees. This process is very computationally intensive; constructing a large phylogenetic tree requires hundreds to thousands of CPU hours. In this article, we describe an FPGA-based system that can be deployed on AWS EC2 F1 c...
Article
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More than 75% of Internet traffic is now encrypted, and this percentage is constantly increasing. The majority of communications are secured using common encryption protocols such as SSL/TLS and IPsec to ensure security and protect the privacy of Internet users. However, encryption can be exploited to hide malicious activities, camouflaged into nor...
Article
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Security and privacy (SP)-related challenges constitute a significant barrier to the wider adoption of Internet of Things (IoT)/Industrial IoT (IIoT) devices and the associated novel applications and services. In this context, patterns, which are constructs encoding re-usable solutions to common problems and building blocks to architectures, can be...
Preprint
Twitter is the third most popular worldwide Online Social Network (OSN) after Facebook and Instagram. Compared to other OSNs, it has a simple data model and a straightforward data access API. This makes it ideal for social network studies attempting to analyze the patterns of online behavior, the structure of the social graph, the sentiment towards...
Article
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The railway transport system is critical infrastructure that is exposed to numerous man-made and natural threats, thus protecting this physical asset is imperative. Cyber security, privacy, and dependability (SPD) are also important, as the railway operation relies on cyber-physical systems (CPS) systems. This work presents SPD-Safe—an administrati...
Chapter
The convergence of Internet of Things (IoT), Cloud, and Big Data, creates new challenges and opportunities for data analytics. Human- and machine-created data is being aggregated continuously, transforming our economy and society. To face these challenges, companies call upon expert analysts and consultants to assist them. In this paper, we present...
Article
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Recommender systems have greatly evolved in recent years and have become an integral part of the Web. From e-commerce sites to mobile apps, our daily routine revolves around a series of “small” decisions that are influenced by such recommendations. In a similar manner, online social networks recommend only a subset of the massive amount of content...
Article
Instruction Set Randomization (ISR) is able to protect against remote code injection attacks by randomizing the instruction set of each process. Thereby, even if an attacker succeeds to inject code, it will fail to execute on the randomized processor. The majority of existing ISR implementations is based on emulators and binary instrumentation tool...
Chapter
Full-text available
The orchestration of heterogeneous IoT devices to enable the provision of IoT applications and services poses numerous challenges, especially in contexts where end-to-end security and privacy guarantees are needed. To tackle these challenges, this paper presents a pattern–driven approach for interacting with IoT systems, whereby the required proper...
Article
Full-text available
Intelligent surfaces exert deterministic control over the wireless propagation phenomenon, enabling novel capabilities in performance, security and wireless power transfer. Such surfaces come in the form of rectangular tiles that cascade to cover large surfaces such as walls, ceilings or building facades. Each tile is addressable and can receive so...
Preprint
A very large number of people use Online Social Networks daily. Such platforms thus become attractive targets for agents that seek to gain access to the attention of large audiences, and influence perceptions or opinions. Botnets, collections of automated accounts controlled by a single agent, are a common mechanism for exerting maximum influence....
Conference Paper
This article presents the cyber security progress in Greece since the creation of the Greek National Cyber Security Authority as a nationwide cybersecurity coordination and policy making unit. During this period, Greece issued a Ministerial Decree that established the National Cyber Security Authority, issued the National Cybersecurity strategy, tr...
Preprint
The upcoming November 2020 presidential elections in the United States have caused extensive discussions on social media. A part of the content on US elections is organic, coming from users discussing their opinions of the candidates, political positions, or relevant content presented on television. Another significant part of the content generated...
Preprint
Intelligent surfaces exert deterministic control over the wireless propagation phenomenon, enabling novel capabilities in performance, security and wireless power transfer. Such surfaces come in the form of rectangular tiles that cascade to cover large surfaces such as walls, ceilings or building facades. Each tile is addressable and can receive so...
Conference Paper
In this paper, we focus on authentication and authorization flaws in web apps that enable partial or full access to user accounts. Specifically, we develop a novel fully automated black-box auditing framework that analyzes web apps by exploring their susceptibility to various cookie-hijacking attacks while also assessing their deployment of pertine...
Article
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Nowadays, more-and-more cyber-security training is emerging as an essential process for the lifelong personnel education in organizations, especially for those which operate critical infrastructures. This is due to security breaches on popular services that become publicly known and raise people’s security awareness. Except from large organizations...
Article
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Key challenges in Internet-of-Things (IoT) system design and management include the secure system composition and the calculation of the security and dependability level of the final system. This paper presents an event-based model-checking framework for IoT systems' design and management, called CompoSecReasoner. It invokes two main functionalitie...
Article
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Metasurfaces, the ultrathin, 2D version of metamaterials, have recently attracted a surge of attention for their capability to manipulate electromagnetic waves. Recent advances in reconfigurable and programmable metasurfaces have greatly extended their scope and reach into practical applications. Such functional sheet materials can have enormous im...
Article
Modern smartphone sensors can be leveraged for providing novel functionality and greatly improving the user experience. However, sensor data can be misused by privacy-invasive or malicious entities. Additionally, a wide range of other attacks that use mobile sensor data have been demonstrated; while those attacks have typically relied on users inst...
Article
The increase in the world's population has led to a massive rise in human consumption of the planet's natural resources, well beyond their replacement rate. Traditional recycling concepts and methods are not enough to counter such effects. In this context, a circular economy (CE), that is, a restorative and regenerative by-design economy, can refor...
Article
Full-text available
Modern educational tools and computer technologies are now getting adapted in the cyber-ranges field. Simulation, emulation, as well as serious gaming provide an enhanced training experience under realistic conditions and accurate operational environments. The THREAT-ARREST Horizon-2020 project is developing a model-driven platform for professional...
Preprint
Programmable wireless environments (PWEs) utilize electromagnetic metasurfaces to transform wireless propagation into a software-controlled resource. In this work we study the effects of user device mobility on the efficiency of PWEs. An analytical model is proposed, which describes the potential misalignment between user-emitted waves and the acti...
Chapter
Full-text available
Insurance of digital assets is becoming an important aspect nowadays, in order to reduce the investment risks in modern businesses. GDPR and other legal initiatives makes this necessity even more demanding as an organization is now accountable for the usage of its client data. In this paper, we present a cyber insurance framework, called CyberSure....
Chapter
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Most of the modern web services offer their users the ability to be registered on them via dedicated registration pages. Most of the times, they use this method so the users can profit by accessing more content or privileged items. In these pages, users are typically requested to provide their names, email addresses, phone numbers and other persona...