Petros Kefalas

Petros Kefalas
The University of Sheffield | Sheffield · Department of Computer Science (International Faculty)

PhD in Computer Science

About

127
Publications
36,334
Reads
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967
Citations
Citations since 2017
16 Research Items
216 Citations
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2017201820192020202120222023010203040
Additional affiliations
January 1993 - August 2016
The University of Sheffield
Position
  • Managing Director
Education
October 1987 - March 1991
University of Essex
Field of study
  • Computer Science
September 1986 - October 1987
University of Essex
Field of study
  • Computer Studies (Artificial Intelligence)
September 1981 - February 1986

Publications

Publications (127)
Book
Full-text available
Artificial Intelligence (in Greek). Η ύλη καλύπτει εκτενώς τόσο τη συμβολική όσο και την υπολογιστική τεχνητή νοημοσύνη και δεν παραλείπει να συμπεριλάβει και νέα θέματα μεγάλου ερευνητικού και εμπορικού ενδιαφέροντος. Αρκετά από αυτά καλύπτονται εκτενώς, κάνοντας το βιβλίο κατάλληλο για χρήση τόσο σε προπτυχιακά όσο και σε μεταπτυχιακά μαθήματα.
Chapter
Agent-based Computational Economics (ACE) is an area that has gained significant attention, since it offers the possibility to model economic phenomena in a more fine-grained manner than other approaches. One such phenomenon is “bank panic” in which the term “panic” implies the existence of emotional bias towards to the sudden withdrawal of deposit...
Presentation
The light-speed advances in technology have had a huge impact on academic staff and their practices. Within this context, our presentation discusses what the academic teacher of the future should look like, focusing on skills and mindset required to address student needs. Aimed primarily to university teachers, subject educators, English language t...
Article
Full-text available
Learning technologies are gradually becoming an integral part of teaching in both face-to-face and online learning. Among them, screencasts (i.e. desktop video recordings of presentations normally accompanied by the presenter’s video and narration), constitute a pedagogical tool used to create visual material to be distributed to students. Learners...
Conference Paper
Involving students in research activities has been credited with many benefits, such as increased critical thinking and analysis skills, development of self-confidence and intellectual independence, and consolidating the ability to ``think like a scientist.'' Student research experiences at undergraduate level have been extensively investigated and...
Conference Paper
Full-text available
In this paper, we present the processes we follow in order to enhance and refine the links between Research and Teaching in Higher Education. The stepping-stones towards the creation of a more engaging research-led learning environment are showcased along with good practices for orienting students towards research. Fostering student-led research co...
Chapter
Cloud e-Learning (CeL) is a new paradigm for e-Learning, aiming towards using any possible learning object from the cloud in a smart way and generate a personalised learning path for individual learners. An issue that appears before the generation of the learning path through automated planning, is to filter a pool of resources that are relevant to...
Chapter
This paper presents our experience in integrating agents and robotics in our Computer Science Curriculum. We present a series of modules throughout our curriculum that progressively address these themes and other AI related topics, which ends with a specialised final year module central to teaching and learning multi-agent systems and principles of...
Conference Paper
Full-text available
Cloud e-Learning (CeL) is a new paradigm for e-Learning, aiming towards using any possible learning object from the cloud in a smart way and generate a personalised learning path for individual learners. An issue that appears before the generation of the learning path through automated planning, is to filter a pool of resources that are relevant to...
Conference Paper
Full-text available
Everything stored on the cloud could potentially be a knowledge source used for e-learning. Given learners’ profiles, desires and feedback on what they have already learned, a new form of personalised e-learning emerges, namely Cloud E- Learning (CeL). CeL should be able to choose from structured to totally unstructured learning material but needs t...
Conference Paper
Screencasts have lately become a pedagogical tool used to create videos to be distributed to students. The plethora of tools make it easier for the teachers to produce high-quality, low-cost screencasts for a number of reasons outlined in the paper. However, in the current work we focus more on how screencasts can be used in a programming course, n...
Conference Paper
This paper discusses the issue of validating simulations that involve emotional agents. In disaster management scenaria, such as emergency evacuations, simulations are developed to demonstrate the behaviour of people acting under emotional pressure. It is implied that the models of agents in such simulations demand the integration of emotions and h...
Conference Paper
This paper describes the rationale, approach and outcomes of the use of Graduate Attributes in Higher Education and a set of badges mapped to each one of them. We decorate syllabi with these badges with the aim of facilitating a programme level view of how any programme of study contributes to the employability profile of our graduates. We suggest...
Conference Paper
Full-text available
Automated planning is being used in various domains for generating processes that require to bridge a current and a desired state of affairs. Learning can be seen as a process that guides a learner to bridge her current knowledge and skills to some desired ones. The main issue is to select the most appropriate learning resources to include in a per...
Conference Paper
Formal modelling of emotions in agents is a challenging task. This is mainly due to the absence of a widely accepted theory of emotions as well as the two-way interaction of emotions with mood, perception, personality, communication, etc. In this work, we use the widely accepted dimensional theory of emotions according to which mood is a significan...
Conference Paper
Emotions have attracted much interest in the MAS community, mainly due to their significance in creating simulations that more accurately predict crowd behaviours. Undoubtedly, infusion of agents with artificial emotions has to be supported by current psychology theories. The present work describes a formal model of artificial emotions based on the...
Conference Paper
The design and delivery of a training programme for counsellors is challenging, because it necessitates considerable enhancement of trainees’ attributes that are key factors for effective counselling. The arising issues are academic, practical and ethical. In this paper, we present a framework developed within a postgraduate programme that ensures...
Conference Paper
Full-text available
In this position paper we describe our experience on developing a newly-set-up learning environment within our University, and we provide examples of various practices within the areas of teaching, learning and assessment, student support, feedback provision, student engagement, staff development etc. Indicative examples of ‘good’ (as opposed to ‘b...
Book
Full-text available
Τεχνικές Λογικού Προγραμματισμού. [ebook] Athens:Hellenic Academic Libraries Link. Available Online at: http://hdl.handle.net/11419/777
Conference Paper
Full-text available
In recent years, personalization and customization in cloud services are more than evident. Cloud e-Learning (CeL) is an upgraded model of traditional e-Learning which aims to offer personalization, collaboration through interaction and structured customized learning content. Cloud e-Learners will express their preferences and be offered courses as...
Conference Paper
Applying the Stream X-Machine formal method in the development of multi-agent simulations has a number of significant advantages, since it combines the power of executable specifications and test case generation. The present work supports this argument by reporting on the combined use of two tools that involve Stream X-Machines (SXM): the first is...
Conference Paper
This work presents an approach to agent-based simulation development using formal modelling, i.e. stream X-Machines, that combines the power of executable specifications and test case generation. In that respect, a domain specific language is presented for effortlessly encoding agent behaviour as a stream X-Machine in a well known simulation platfo...
Conference Paper
Full-text available
There is an increasing interest in modelling of agents interacting as crowd and a simulation of such scenarios that map to real-life situations. This paper presents a generic state-based abstract model for crowd behaviour that can be mapped onto different agent-based systems. In particular, the abstract model is mapped into the simulation framework...
Article
Targeted drug delivery with the use of nanorobots, a yet mostly theoretical but very promising future concept, is anticipated to become a significant ally in cancer treatment. The way that nanorobot systems are currently envisaged by researchers is such that they exhibit autonomous and collaborative behaviour that can be uniquely captured by multi-...
Conference Paper
Multi-agent systems simulation is used to predict human behaviour in emergency evacuation cases. However, as human behaviour can change under the effect of emotions, it is essential to create models of artificial agents and simulations that mimic such behaviour in order to make prediction of the overall system performance. In emotional agents, the...
Conference Paper
Emotions in Agent and Multi-Agent Systems change their behaviour to a more ’natural’ way of performing tasks thus increasing believability. This has various implications on the overall performance of a system. In particular in situations where emotions play an important role, such as disaster management, it is a challenge to infuse artificial emoti...
Conference Paper
Full-text available
Higher Education (HE) institutions need to rethink their role within the context of economic crisis and globalisation. To this end, the concept of the entrepreneurial university, intertwined with internationalization, comes as a possible central solution to the challenge of delivering high-quality global education. Economies in transition are seeki...
Article
Evacuation Simulation is recognised as an important tool for assessing design choices for urban areas. Although a number of approaches have been introduced, it is widely acceptable that such simulation scenarios demand modelling of emotional aspects of evacuees, and how these affect their behaviour. The present work, proposes that formal agent mode...
Chapter
Full-text available
The developments of pedagogical models in e-learning together with the advances of learning technologies and cloud computing give us confidence to believe that the traditional e-learning will evolve into a process which will put the learner in the center of educational provision. This paper proposes that Cloud e-Learning, a new approach to e-learni...
Conference Paper
Nanorobots, a yet theoretical but very promising future concept, is anticipated to introduce powerful solutions to human health problems. The way that nanorobot systems are currently envisaged by researchers is such that they exhibit behaviour that can be uniquely captured with use of multi-agent based simulations. In this paper, we investigate thi...
Conference Paper
Full-text available
Applications of biological or biologically inspired multi-agent systems (MAS) often assume a certain level of reliability and robustness, which is not always straightforward. Formal modelling and verification of MAS may present many interesting challenges. For instance, formal verification may be cumbersome or even impossible to be applied on model...
Article
Full-text available
Archiving versions of academic documents in consideration of green thinking was the motivation to develop an innovative tool that could organize academic documents in a centralized database. This paper presents a new web application, which aims to move towards a paperless University model for managing academic documents that are used within an edu...
Conference Paper
Crowd behaviour deviates from normal when an emergency evacuation is needed. Thus, simulation of evacuation situations has been identified as an important tool for assessing design choices of urban areas, such as buildings, stadiums, etc., and Agent Based Modelling has been employed to tackle such problems. In this paper, we propose that formal mod...
Conference Paper
Artificial Agents infused with emotions have attracted considerable attention in recent years. Many domain areas require agents to be able to demonstrate an emotional reaction to stimuli, beliefs, goals, communication etc., thus exhibiting a believable behaviour. On the other hand, little has been said on how formal methods could integrate emotions...
Conference Paper
Full-text available
For many years entrepreneurship education was mostly integrated within the academic fields of business and management. Recently though, entrepreneurship education has expanded the boundaries of purely business education to other specialised sectors such as technology and science, promoting thus the need of introducing the teaching of entrepreneursh...
Conference Paper
Full-text available
Simulation of crowd behaviours has long been an area of active research due to its high impact on urban area design. Rather recently, the problem has been tackled using agent based simulation (ABMS), a modelling approach that offers a more natural and flexible method for describing pedestrian behaviour. The current work, concerns ABMS modelling of...
Conference Paper
Full-text available
Modelling and verification of spatial multi-agent systems present many interesting challenges, especially when it comes to reliability and robustness. Among other characteristics, these systems are commonly composed of spatial properties which typically cannot be formally verified due to combinatorial explosion. Verification of these systems can be...
Article
Full-text available
Entrepreneurialism and internationalisation have been one of the main drivers for change in the higher education sector. In this paper, we present our experience and elaborate on the case of CITY College based in Thessaloniki-Greece, as a model for international development. The case has the unique characteristic that it has evolved as an Internati...
Conference Paper
Full-text available
Starting with the notion of modelling biologically inspired agents, this paper throws focus on their spatial characteristics. As dis- cussed, one of the most prominent formalisms in modelling the behaviour of biological colonies, X-machines, cannot provide a standardised way to modelling spatial agents. Along these lines, this paper introduces an X...
Conference Paper
Entrepreneurialism and internationalisation have been one of the main drivers for change in the higher education sector. In this paper, we present our experience and elaborate on the case of CITY College based in Thessaloniki-Greece, as a model for international development. The case has the unique characteristic that it has evolved as an Internati...
Conference Paper
Universities have to rethink their role within the context of economic crisis and globalisation. Especially entrepreneurial Universities can act as regional development boosters, as long as they are committed to a strategic vision with flexibility and prompt action with entrepreneurial spirit and goals for internationalisation. Economies in transit...
Article
Full-text available
Universities have to rethink their role within the context of economic crisis and globalisation. Especially entrepreneurial Universities can act as regional development boosters, as long as they are committed to a strategic vision with flexibility and prompt action with entrepreneurial spirit and goals for internationalisation. Economies in transit...
Chapter
As part of designing a new Master’s programme entitled Technology, Innovation and Entrepreneurship there was an apparent need to include a unit involving the use of innovative technologies for the development of innovative products and services. The authors aim was therefore to introduce students to Artificial Intelligence and Intelligent Agents us...
Conference Paper
Full-text available
Applications of biological or bio-inspired multi-agent systems often assume a certain level of reliability and robustness. Formal modelling of such systems can naturally lead to formal verification of their properties. State-based approaches to formal modelling, such a X-Machines, have been demonstrated as a good candidate for modelling biological...
Conference Paper
Full-text available
This work concentrates on the behaviour of biological multiagent systems that consists of communities evolving in space and time, such as social insects, tissues, colonies of bacteria, etc. Such complex systems that characterise with a highly dynamic structure can be modelled by utilizing population P systems with active cells. This class of P syst...
Conference Paper
Full-text available
Formal development of agent systems with inherent high complexity is not a trivial task, especially if a formal method used is not accompanied by an appropriate methodology. X-machines is a formal method that resembles Finite State Machines but has two important extensions, namely internal memory structure and functions. In this paper, we present a...
Conference Paper
Full-text available
Formal modelling of multi-agent systems (MAS) present many interesting challenges. In this extended abstract we present a framework of how formal modelling can lead towards identification and verification of emergent properties of spatial biology-inspired MAS. We discuss the problem in question as well as initial work done on the formal modelling s...
Conference Paper
Full-text available
This paper starts with a brief review of existing formal techniques used to model biology-inspired Multi-agent systems (MAS). Certain shortcomings of each are identified and towards this direction, we make our initial proposal for further research directions. We concentrate on a particular aspect, namely MAS simulation. We focus on a simulation pla...
Conference Paper
Full-text available
Intelligent agents are classified into various types depending on whether they just react to the stimuli they perceive (reactive) or they develop plans to solve their own goals (proactive or goal-oriented). In practice, agents are a mixture of two layers since they perform reactive or proactive tasks depending on what is the most appropriate at a g...
Conference Paper
Full-text available
Formal modelling of Multi-Agent Systems (MAS) is a challenging task due to high complexity, interaction, parallelism and continuous change of roles and organisation between agents. In this paper we record our research experience on formal modelling of MAS. We review our research throughout the last decade, by describing the problems we have encount...
Chapter
In the context of an Agent and Multi-Agent Systems course, exposing students to problems and issues related to agent-based programming allows them to understand at a deeper level the otherwise theoretical aspects involved in the design of a multi-agent system (MAS). Indeed, educators have reported a variety of environments and techniques they use i...
Chapter
As part of designing a new Master's programme entitled Technology, Innovation and Entrepreneurship there was an apparent need to include a unit involving the use of innovative technologies for the development of innovative products and services. The authors aim was therefore to introduce students to Artificial Intelligence and Intelligent Agents us...
Chapter
In the context of an Agent and Multi-Agent Systems course, exposing students to problems and issues related to agent-based programming allows them to understand at a deeper level the otherwise theoretical aspects involved in the design of a multi-agent system (MAS). Indeed, educators have reported a variety of environments and techniques they use i...
Chapter
As part of designing a new Master’s programme entitled Technology, Innovation and Entrepreneurship there was an apparent need to include a unit involving the use of innovative technologies for the development of innovative products and services. The authors aim was therefore to introduce students to Artificial Intelligence and Intelligent Agents us...
Article
Full-text available
Tissue P systems represent a class of P systems in which cells are arranged in a graph rather than a hierarchical structure. On the other hand, communicating X-machines are state-based machines, extended with a memory structure and transition functions instead of simple inputs, which communicate via message passing. One could use communicating X-ma...
Article
Full-text available
In the context of an Intelligent Agents course, we have cho-sen NetLogo as the means to satisfy the students' demand for hands-on practice, to help them understand at a deeper level the otherwise theoretical aspects involved in the design of a multi-agent system (MAS). In this paper we present in detail the structure of the two pieces of coursework...
Conference Paper
Full-text available
The implementation process of complex agent and multi-agent systems (AMAS) can benefit significantly from a simulation platform that would allow rapid prototyping and testing of initial design ideas and choices. Such a platform, should ideally have a small learning curve, easy implementation and visualisation of the AMAS under development, while pr...
Conference Paper
The demand for more complex software is constantly increasing while at the same time the need for reliability leads modern software engineering to use more formally based development techniques. One of the most successfully employed formalisms to address the reliability issue were Finite State Machines (FSM) but they are too simple to capture the m...
Conference Paper
We present an automatic practical transformation of Communicating X-machines to Population P Systems. The resulting compiler is able to take as input a Communicating X-machine model written in an appropriately designed language (XMDL) and produce a Population P System in another notation (PPSDL). The latter contains only transformation and communic...
Article
Full-text available
Recent advances in both the testing and verification of software based on formal specifications of the system to be built have reached a point where the ideas can be applied in a powerful way in the design of agent-based systems. The software engineering research has highlighted a number of important issues: the importance of the type of modelling...
Article
Full-text available
During the last decade, our involvement with discussing with potential students and their parents before they apply for an undergraduate Computer Science programme, made us realise that there exist patterns in people's minds about Computer Science studies and profession. These patterns form misconceptions, which we identified as myths. In this pape...
Article
Social insect colonies present an interesting problem for formal modelling due to characteristics such as self-organisation and dynamic structure. In this paper, we present a formal model of a colony of Pharaoh ants using OPERASXP , which combines two different formal methods, communicating X- machines and population P systems as well as a framewor...
Conference Paper
Full-text available
Swarm-based systems are a class of multi-agent systems (MAS) of particular interest because they exhibit emergent behaviour through self-organisation. They are biology-inspired but find themselves applicable to a wide range of domains, with some of them characterised as mission critical. It is therefore implied that the use of a formal framework an...
Article
Full-text available
We present OPERAS, a formal method that facilitates the development of biologically inspired multi-agent systems exhibiting emergent behaviour through self-organisation. We describe how a particular version of this method, namely OPERAS XC , could employ and integrate the most prominent characteristics of finite state machines and biological comput...
Article
The paper discusses the modelling aspects of systems with dynamic processes and dynamic structure. A combination of models bringing together the benefits of two paradigms, Population P Systems and Communicating X-machines, is introduced. A simple case study is used in order to illustrate the potential of the combined use of the two methods.
Article
Full-text available
Social insect colonies present an interesting problem for formal modelling due to their outstanding characteristics, such as self-organisation and emergence. In this paper, we experiment with two different formal methods, Communicating X-machines and Population P Systems, which can be used separately to model biologically inspired. systems. The cas...
Article
Full-text available
Logic Programming (LP) courses are part of many Computer Science or Artificial Intelligence related programmes. In this paper, we present a systematic approach on teaching an LP course, using Prolog as the main computational paradigm. We argue that LP is an excellent didactic tool for teaching Intelligent Programming Systems as well as a vehicle fo...
Article
Full-text available
Population P Systems is a class of P Systems in which cells are arranged in a graph rather than a hierarchical structure. On the other hand, Communicating X-machines are state-based machines, extended with a memory structure and transition functions instead of simple inputs, which communicate via message passing. One could use Communicating X-machi...