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All Outputs (23)

A Deep Learning Approach for Paragraph-Level Paraphrase Generation for Plagiarism Detection (2025)
Journal Article
Saqaabi, A. A., Stewart, C., Akrida, E., & Cristea, A. I. (2025). A Deep Learning Approach for Paragraph-Level Paraphrase Generation for Plagiarism Detection. Neural Processing Letters, 57, 59. https://doi.org/10.1007/s11063-025-11771-9

Expressing information in different forms is an important skill that students should develop in school. This skill positively impacts academic reading and writing. However, it can also lead to negative consequences, such as plagiarism. Students may p... Read More about A Deep Learning Approach for Paragraph-Level Paraphrase Generation for Plagiarism Detection.

A Pedagogical Framework for Developing Abstraction Skills (2025)
Presentation / Conference Contribution
Begum, M., Crossley, J., Strömbäck, F., Akrida, E., Alpizar-Chacon, I., Evans, A., Gross, J. B., Haglund, P., Lonati, V., Satyavolu, C., & Thorgeirsson, S. (2025). A Pedagogical Framework for Developing Abstraction Skills. ITiCSE 2024: 2024 Working Group Reports on Innovation and Technology in Computer Science Education (pp. 258-299). ACM. https://doi.org/10.1145/3689187.3709613

Abstraction is a fundamental yet challenging skill to teach and learn in Computer Science education. Traditional frameworks of abstraction and concept formation often emphasize understanding an abstraction over its application, the latter being criti... Read More about A Pedagogical Framework for Developing Abstraction Skills.

Designing a Pedagogical Framework for Developing Abstraction Skills (2024)
Presentation / Conference Contribution
Begum, M., Crossley, J., Strömbäck, F., Akrida, E., Alpizar-Chacon, I., Evans, A., Gross, J. B., Haglund, P., Lonati, V., Satyavolu, C., & Thorgeirsson, S. (2024, July 8-10). Designing a Pedagogical Framework for Developing Abstraction Skills [Conference Abstract]. ITiCSE 2024: Innovation and Technology in Computer Science Education, Milan Italy. https://doi.org/10.1145/3649405.3659533

A Paraphrase Identification Approach in Paragraph Length Texts (2023)
Presentation / Conference Contribution
Saqaabi, A. A. L., Akrida, E., Cristea, A., & Stewart, C. (2023). A Paraphrase Identification Approach in Paragraph Length Texts. 2022 IEEE International Conference on Data Mining Workshops (ICDMW) (2022-November, pp. 358-367). https://doi.org/10.1109/ICDMW58026.2022.00055

Measuring the semantic similarity of natural language is a fundamental issue in many tasks, such as paraphrase identification (PI) and plagiarism detection (PD) which are intended to solve maj or issues in education. Various approaches that have been... Read More about A Paraphrase Identification Approach in Paragraph Length Texts.

Narrowing and Stretching: Addressing the Challenge of Multi-track Programming (2022)
Presentation / Conference Contribution
Bradley, S., & Akrida, E. (2022). Narrowing and Stretching: Addressing the Challenge of Multi-track Programming. Proceedings of the 6th Conference on Computing Education Practice CEP 2022 (pp. 1-4). ACM. https://doi.org/10.1145/3498343.3498344

Given the different amount of programming experience that students have arriving at university, some universities have introduced alternative multiple streams to teach programming. This approach was exemplified by Harvey Mudd College, who successfull... Read More about Narrowing and Stretching: Addressing the Challenge of Multi-track Programming.

Connected Subgraph Defense Games (2021)
Journal Article
Akrida, E. C., Deligkas, A., Melissourgos, T., & Spirakis, P. G. (2021). Connected Subgraph Defense Games. Algorithmica, 83(11), 3403-3431. https://doi.org/10.1007/s00453-021-00858-z

We study a security game over a network played between a defender and k attackers. Every attacker chooses, probabilistically, a node of the network to damage. The defender chooses, probabilistically as well, a connected induced subgraph of the networ... Read More about Connected Subgraph Defense Games.

The temporal explorer who returns to the base (2021)
Journal Article
Akrida, E. C., Mertzios, G. B., Spirakis, P. G., & Raptopoulos, C. (2021). The temporal explorer who returns to the base. Journal of Computer and System Sciences, 120, 179-193. https://doi.org/10.1016/j.jcss.2021.04.001

We study here the problem of exploring a temporal graph when the underlying graph is a star. The aim of the exploration problem in a temporal star is finding a temporal walk which starts and finishes at the center of the star, and visits all leaves.... Read More about The temporal explorer who returns to the base.

How fast can we reach a target vertex in stochastic temporal graphs? (2020)
Journal Article
Akrida, E. C., Mertzios, G. B., Nikoletseas, S., Raptopoulos, C., Spirakis, P. G., & Zmaraev, V. (2020). How fast can we reach a target vertex in stochastic temporal graphs?. Journal of Computer and System Sciences, 114, 65-83. https://doi.org/10.1016/j.jcss.2020.05.005

Temporal graphs abstractly model real-life inherently dynamic networks. Given a graph G, a temporal graph with G as the underlying graph is a sequence of subgraphs (snapshots) of G, where . In this paper we study stochastic temporal graphs, i.e. stoc... Read More about How fast can we reach a target vertex in stochastic temporal graphs?.

Connected Subgraph Defense Games (2019)
Book Chapter
Akrida, E. C., Deligkas, A., Melissourgos, T., & Spirakis, P. G. (2019). Connected Subgraph Defense Games. Algorithmic Game Theory (pp. 216-236). Springer Verlag. https://doi.org/10.1007/978-3-030-30473-7_15

We study a security game over a network played between a defender and k attackers. Every attacker chooses, probabilistically, a node of the network to damage. The defender chooses, probabilistically as well, a connected induced subgraph of the networ... Read More about Connected Subgraph Defense Games.

Temporal vertex cover with a sliding time window (2019)
Journal Article
Akrida, E. C., Mertzios, G. B., Spirakis, P. G., & Zamaraev, V. (2020). Temporal vertex cover with a sliding time window. Journal of Computer and System Sciences, 107, 108-123. https://doi.org/10.1016/j.jcss.2019.08.002

Modern, inherently dynamic systems are usually characterized by a network structure which is subject to discrete changes over time. Given a static underlying graph, a temporal graph can be represented via an assignment of a set of integer time-labels... Read More about Temporal vertex cover with a sliding time window.

How fast can we reach a target vertex in stochastic temporal graphs? (2019)
Presentation / Conference Contribution
Akrida, E. C., Mertzios, G. B., Nikoletseas, S., Christoforos, R., Spirakis, P. G., & Zamaraev, V. (2019). How fast can we reach a target vertex in stochastic temporal graphs?. In C. Baier, I. Chatzigiannakis, P. Flocchini, & S. Leonardi (Eds.), 46th International Colloquium on Automata, Languages, and Programming (ICALP 2019) (pp. 131:1-131:14). Dagstuhl Publishing. https://doi.org/10.4230/lipics.icalp.2019.131

Temporal graphs are used to abstractly model real-life networks that are inherently dynamic in nature, in the sense that the network structure undergoes discrete changes over time. Given a static underlying graph G=(V,E), a temporal graph on G is a s... Read More about How fast can we reach a target vertex in stochastic temporal graphs?.

On Verifying and Maintaining Connectivity of Interval Temporal Networks (2019)
Journal Article
Akrida, E. C., & Spirakis, P. G. (2019). On Verifying and Maintaining Connectivity of Interval Temporal Networks. Parallel Processing Letters, 29(02), 1950009. https://doi.org/10.1142/s0129626419500099

An interval temporal network is, informally speaking, a network whose links change with time. The term interval means that a link may exist for one or more time intervals, called availability intervals of the link, after which it does not exist (unti... Read More about On Verifying and Maintaining Connectivity of Interval Temporal Networks.

The temporal explorer who returns to the base (2019)
Presentation / Conference Contribution
Akrida, E. C., Mertzios, G. B., & Spirakis, P. G. (2019). The temporal explorer who returns to the base. In P. Heggernes (Ed.), Algorithms and Complexity (CIAC 2019); 11th International Conference, CIAC 2019, Rome, Italy, May 27–29, 2019 ; proceedings. (pp. 13-24). Springer Verlag. https://doi.org/10.1007/978-3-030-17402-6_2

In this paper we study the problem of exploring a temporal graph (i.e. a graph that changes over time), in the fundamental case where the underlying static graph is a star on n vertices. The aim of the exploration problem in a temporal star is to fin... Read More about The temporal explorer who returns to the base.

Temporal flows in temporal networks (2019)
Journal Article
Akrida, E. C., Czyzowicz, J., Gąsieniec, L., Kuszner, Ł., & Spirakis, P. G. (2019). Temporal flows in temporal networks. Journal of Computer and System Sciences, 103, 46-60. https://doi.org/10.1016/j.jcss.2019.02.003

We introduce temporal flows on temporal networks. We show that one can find the maximum amount of flow that can pass from a source vertex s to a sink vertex t up to a given time in Polynomial time. We provide a static Time-Extended network (TEG) of p... Read More about Temporal flows in temporal networks.

Temporal vertex cover with a sliding time window (2018)
Presentation / Conference Contribution
Akrida, E. C., Mertzios, G. B., Spirakis, P. G., & Zamaraev, V. (2018). Temporal vertex cover with a sliding time window. In I. Chatzigiannakis, C. Kaklamanis, D. Marx, & D. Sannella (Eds.), 45th International Colloquium on Automata, Languages, and Programming (ICALP 2018) : Prague, Czech Republic, July 9-13, 2018 ; proceedings. (107, pp. 148:1-148:14). Schloss Dagstuhl – Leibniz-Zentrum für Informatik. https://doi.org/10.4230/lipics.icalp.2018.148

Modern, inherently dynamic systems are usually characterized by a network structure, i.e. an underlying graph topology, which is subject to discrete changes over time. Given a static underlying graph G, a temporal graph can be represented via an assi... Read More about Temporal vertex cover with a sliding time window.

Temporal Flows in Temporal Networks (2017)
Presentation / Conference Contribution
Akrida, E. C., Czyzowicz, J., Gąsieniec, L., Kuszner, Ł., & Spirakis, P. G. (2017). Temporal Flows in Temporal Networks. Algorithms and Complexity (10236, pp. 43-54). Springer Verlag. https://doi.org/10.1007/978-3-319-57586-5_5

We introduce temporal flows on temporal networks [17, 19], i.e., networks the links of which exist only at certain moments of time. Such networks are ephemeral in the sense that no link exists after some time. Our flow model is new and differs from t... Read More about Temporal Flows in Temporal Networks.

The complexity of optimal design of temporally connected graphs (2017)
Journal Article
Akrida, E. C., Gasieniec, L., Mertzios, G. B., & Spirakis, P. G. (2017). The complexity of optimal design of temporally connected graphs. Theory of Computing Systems, 61(3), 907-944. https://doi.org/10.1007/s00224-017-9757-x

We study the design of small cost temporally connected graphs, under various constraints. We mainly consider undirected graphs of n vertices, where each edge has an associated set of discrete availability instances (labels). A journey from vertex u t... Read More about The complexity of optimal design of temporally connected graphs.

On temporally connected graphs of small cost (2016)
Presentation / Conference Contribution
Akrida, E. C., Gasieniec, L., Mertzios, G. B., & Spirakis, P. G. (2016). On temporally connected graphs of small cost. Approximation and online algorithms : 13th International Workshop, WAOA 2015, Patras, Greece, September 17-18, 2015. Revised selected papers. (pp. 84-96). Springer Verlag. https://doi.org/10.1007/978-3-319-28684-6_8

We study the design of small cost temporally connected graphs, under various constraints. We mainly consider undirected graphs of n vertices, where each edge has an associated set of discrete availability instances (labels). A journey from vertex u t... Read More about On temporally connected graphs of small cost.