Systems supporting argumentation exist for a long time and have appeared with many different forms, ranging from online forums, to mind maps and decision support systems. These systems are used daily by teams that collaborate in data intensive and cognitive complex settings, such as teams involved in DNA analysis and social media research. However, current argumentation support systems do not offer the required functionalities for the meaningful analysis and aggregation of the associated complex data, thus not properly serving requirements related to gaining of insights and decision making. Aiming to address these issues, this paper presents an approach that integrates argumentation support services with data mining and natural language processing services to augment collaboration and decision making in the above teams. The proposed approach builds on well-tried principles of hypertext systems and adopts a service-oriented architecture to enable the contextualization of the foreseen services, as well as their execution and integration of their results in the argumentative discourse, hence facilitating its monitoring and understanding.

Effective teaching of concepts related to human computer interaction (HCI) requires introduction of the core paradigms as well as the design and evaluation methodologies to the learners. In this paper, we investigate the learning effectiveness of a tool-mediated learning activity to support instruction of established human performance models, namely the Keystroke Level Model (KLM) and Fitts’ law, and their application in web form design practice. The tool, named Keystroke Level Model Form Analyser (KLM-FA), supports learning through exploration by providing step-by-step tracing of the KLM modelling for any web form filling task. KLM-FA can be used in modelling exercises of either online or offline web forms according to different interaction strategies or users’ characteristics. Three pretest-posttest studies involving 52 students in total enrolled in computer science curricula with different education delivery methods (campus-based, blended learning, distance learning) and levels (undergraduate, postgraduate) provide evidence for the effectiveness of the proposed learning activity. In all three studies, it was found that the KLM-FA activity had a significant positive effect on students’ learning gain. In addition, students rated their perceived educational experience and KLM-FA usability as rather high. Content analysis of students’ comments also found that KLM-FA is an educationally valuable and usable tool.

The outbreak of the COVID-19 pandemic forced Universities to adopt new approaches in both deliver their learning activities and carry out the examinations. The remote examination approach was selected in order to overcome the limitation of students' physical presence in examination centers. This paper presents the evaluation of the remote examinations conducted by the Hellenic Open University. A sample of 9.276 students participated in order to fill out anonymously a short questionnaire that consists of 11 questions (8 closed-ended Likert-like and 3 open-ended). Both qualitative and quantitative analysis was employed. Analysis revealed that students were satisfied in general from the remote examination process and they expressed their desire to be examined remotely in the future. To the best of our knowledge, this is the first large-scale study of a remote examination process in our country.

HCI researchers and practitioners are increasingly using physiological data to measure User eXperience (UX) parameters. The dynamic nature of physiological data offers a continuous window for an in-depth understanding of users’ interaction experience. However, in order to be truly informative, physiological signals need to be linked to users’ interaction experience aspects, such as their emotional states, in a systematic and efficient way. Studies have shown that skin conductance is a physiological signal highly associated with stress. The main purpose of this paper is to present the validation study of our proposed stress detection mechanism which is integrated into a software named PhysiOBS. PhysiOBS is an observation analysis tool that can be used in the post-study analysis phase. PhysiOBS uses nonspecific skin conductance responses (NS-SCRs) in order to auto-report time periods that are probably associated with a problematic interaction. PhysiOBS can also combine multiple data sources. Hence, UX evaluators are able to further investigate a recorded session in order to reveal additional interaction flaws. The integrated stress assessment mechanism, which uses four trained classifiers, can be applied in the reported periods (auto/expert-reported) in order to classify them as stress or non-stress. For the purpose of the validation study, 24 users were recruited in order to participate in a lab experiment. Results showed that our stress assessment mechanism supports UX evaluators by accurately identifying stressful regions within an interaction scenario.

While logic locking is a promising defense to protect hardware designs, many attacks have been shown to undermine its security by retrieving the secret key. All the powerful attacks rely on a working chip, i.e., an oracle, and in particular, heavily use the test access. The proposed technique DisORC turns the oracle into a dishonest one whenever a potential attack is detected. DisORC works on the premise that structural testing of chips need not be performed with the correct functionality. We implement this capability by adding circuitry around a logic-locked design that reconfigures its functionality upon detecting access to scan chains. Any attempt to access scan chains disconnects the secret key from the circuit, and clears all of its traces, isolating and securing it. We also pair this defense with a truly random logic locking (TRLL) scheme that makes random decisions in inserting key gates and retaining signal polarities without relying on any logic synthesis technique to perform bubble pushing. Any netlist analysis-based attack, known or anticipated, will then learn nothing useful to infer the key values. The combined defense DisORC + TRLL thwarts oracle-based and netlist analysis-based attacks while delivering sufficient corruption levels at the outputs. We also show that the proposed defense is cost effective and can be integrated into the design flow easily. The proposed logic locking defense provides protection against untrusted foundry, testing facility, end users, and any combination of them colluding together.

Logic locking has received a lot of attention in the literature due to its very attractive hardware-security characteristics: it can protect against IP piracy and overproduction throughout the whole IC supply chain. However, a large class of logic-locking attacks, the oracle-based ones, take advantage of a functional copy of the chip, the oracle, to extract the key that protects the chip. So far, the techniques dealing with oraclebased attacks focus on the netlist that the attacker possesses, assuming that the oracle is always available. For this reason, they are usually overcome by new attacks. In this paper, we propose a hardware security scheme that targets the protection of the oracle circuit, by locking the circuit when the, necessary for setting the inputs and observing the outputs, scan in/out process begins. Hence, no correct input/output pairs can be acquired to perform the attacks. The proposed scheme is not based on controlling global signals like test enable or scan enable, whose values can be easily suppressed by the attacker. Security threats are identified, discussed and addressed. The developed scheme is combined with a traditional logic locking technique with high output corruptibility, to achieve increased levels of protection.

Logic locking has been successfully used for protecting digital circuits against IC piracy. Modern logic locking techniques offer significant security advantages, like high corruptibility of the locked circuit's outputs when applying random keys (= 50% Hamming Distance-HD-compared to the correct outputs), or resilience to the key-sensitization attack. However, there are no techniques to combine both advantages. To solve this problem, weighted logic locking is proposed in this paper. Instead of the conventional single key-input control, the proposed technique uses multiple key-inputs to control every key-gate. This new, weighted key-gate control is by construction immune to the key-sensitization attack, while by employing a new key-gate insertion metric, 50% HD is obtained even for circuits with many outputs. Additionally, weighted key-gate control increases dramatically the probability of any key-gate to corrupt the circuit's values, which means that fewer key-gates are needed to achieve 50% HD. This way, execution time for locking the circuits is drastically reduced. Apart from these advantages, weighted logic locking is fairly “generic” and can be combined with other techniques to improve security (e.g., to thwart the SAT attack).

We present CoPe_it!, an innovative web-based tool that complies with collaborative practices to provide members of diverse communities with the appropriate means to manage individual and collective knowledge during a complex sense-making and/or decision-making session. We discuss the rationale behin

Hypermedia systems and more specifically open hypermedia systems (OHS) provide a rich set of implementations of different hypertext flavors such as navigational hypertext, spatial hypertext or taxonomic hypertext. Additionally, these systems offer component-based modular architectures and address interoperability between hypertext domains. Despite multiple efforts of integrating Web clients, a widespread adoption of OHS technology by Web developers has not taken place. In this paper it is argued that Web Services - which offer a component model for Web applications - can be integrated in OHSs. An architectural integration is proposed, a step-by-step process is outlined and an example of integration is provided. This very approach is aimed to benefit both worlds: the Web community with new rich hypermedia functionality that extends the current navigational hypermedia, and the OHS community by opening its tools and platforms to the many developer groups of the Web community.