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Publications (10 of 111) Show all publications
Säfvenberg, R., Carlsson, N. & Lambrix, P. (2024). Identifying Player Roles in Ice Hockey. In: Ulf Brefeld, Jesse Davis, Jan Van Haaren, Albrecht Zimmermann (Ed.), Machine Learning and Data Mining for Sports Analytics: 10th International Workshop, MLSA 2023, Turin, Italy, September 18, 2023, Revised Selected Papers. Paper presented at 10th Workshop on Machine Learning and Data Mining for Sports Analytics (pp. 131-143). Springer Nature Switzerland
Open this publication in new window or tab >>Identifying Player Roles in Ice Hockey
2024 (English)In: Machine Learning and Data Mining for Sports Analytics: 10th International Workshop, MLSA 2023, Turin, Italy, September 18, 2023, Revised Selected Papers / [ed] Ulf Brefeld, Jesse Davis, Jan Van Haaren, Albrecht Zimmermann, Springer Nature Switzerland , 2024, p. 131-143Conference paper, Published paper (Refereed)
Abstract [en]

Understanding the role of a particular player, or set of players, in a team is an important tool for players, scouts, and managers, as it can improve training, game adjustments and team construction. In this paper, we propose a probabilistic method for quantifying player roles in ice hockey that allows for a player to belong to different roles with some probability. Using data from the 2021–2022 NHL season, we analyze and group players into clusters. We show the use of the clusters by an examination of the relationship between player role and contract, as well as between role distribution in a team and team success in terms of reaching the playoffs.

Place, publisher, year, edition, pages
Springer Nature Switzerland, 2024
Series
Communications in Computer and Information Science, ISSN 1865-0929, E-ISSN 1865-0937 ; 2035
Keywords
sports analytics, ice hockey
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-201162 (URN)10.1007/978-3-031-53833-9_11 (DOI)9783031538322 (ISBN)9783031538339 (ISBN)
Conference
10th Workshop on Machine Learning and Data Mining for Sports Analytics
Available from: 2024-02-25 Created: 2024-02-25 Last updated: 2024-02-28Bibliographically approved
Bruhner, C. M., Hasselquist, D. & Carlsson, N. (2023). Bridging the Privacy Gap: Enhanced User Consent Mechanisms on the Web. In: Proc. NDSS Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb @NDSS): . Paper presented at Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb) 2023, San Diego, CA, USA, 3 March, 2023.
Open this publication in new window or tab >>Bridging the Privacy Gap: Enhanced User Consent Mechanisms on the Web
2023 (English)In: Proc. NDSS Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb @NDSS), 2023Conference paper, Published paper (Refereed)
Abstract [en]

In the age of the General Data Protection Regula-tion (GDPR) and the California Consumer Privacy Act (CCPA),privacy and consent control have become even more apparent forevery-day web users. Privacy banners in all shapes and sizes askfor permission through more or less challenging designs and makeprivacy control more of a struggle than they help users’ privacy.In this paper, we present a novel solution expanding the AdvancedData Protection Control (ADPC) mechanism to bridge currentgaps in user data and privacy control. Our solution moves theconsent control to the browser interface to give users a seamlessand hassle-free experience, while at the same time offering contentproviders a way to be legally compliant with legislation. Throughan extensive review, we evaluate previous works and identifycurrent gaps in user data control. We then present a blueprintfor future implementation and suggest features to support privacycontrol online for users globally. Given browser support, thesolution provides a tangible path to effectively achieve legallycompliant privacy and consent control in a user-oriented mannerthat could allow them to again browse the web seamlessly.

National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-199090 (URN)10.14722/madweb.2023.23017 (DOI)1891562878 (ISBN)
Conference
Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb) 2023, San Diego, CA, USA, 3 March, 2023
Note

Best paper runner-up award

Available from: 2023-11-11 Created: 2023-11-11 Last updated: 2023-11-16Bibliographically approved
Carlsson, N. & Eager, D. (2023). Cross-user Similarities in Viewing Behavior for 360°Video and Caching Implications. ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP), 19(5), Article ID 152.
Open this publication in new window or tab >>Cross-user Similarities in Viewing Behavior for 360°Video and Caching Implications
2023 (English)In: ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP), ISSN 1551-6857, E-ISSN 1551-6865, Vol. 19, no 5, article id 152Article in journal (Refereed) Published
Abstract [en]

The demand and usage of 360°video services are expected to increase. However, despite these services being highly bandwidth intensive, not much is known about the potential value that basic bandwidth saving techniques such as server or edge-network on-demand caching (e.g., in a CDN) could have when used for delivery of such services. This problem is both important and complicated as client-side solutions have been developed that split the full 360°view into multiple tiles, and adapt the quality of the downloaded tiles based on the user’s expected viewing direction and bandwidth conditions. This paper presents new trace-based analysis methods that incorporate users’ viewports (the area of the full 360°view the user actually sees), a first characterization of the cross-user similarities of the users’ viewports, and a trace-based analysis of the potential bandwidth savings that caching-based techniques may offer under different conditions. Our analysis takes into account differences in the time granularity over which viewport overlaps can be beneficial for resource saving techniques, compares and contrasts differences between video categories, and accounts for uncertainties in the network conditions and the prediction of the future viewing direction when prefetching. The results provide substantial insight into the conditions under which overlap can be considerable and caching effective, and inform the design of new caching system policies tailored for 360°video.

Place, publisher, year, edition, pages
ASSOC COMPUTING MACHINERY, 2023
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-188889 (URN)10.1145/3507917 (DOI)001018509300001 ()
Funder
Swedish Research Council
Note

Funding: Swedish Research Council (VR)

Available from: 2022-09-29 Created: 2022-09-29 Last updated: 2023-08-30
Le, M. H. & Carlsson, N. (2023). IdDecoder: A Face Embedding Inversion Tool and its Privacy and Security Implications on Facial Recognition Systems. In: Proceedings of the Thirteenth ACM Conference on Data and Application Security and Privacy: . Paper presented at CODASPY '23: Thirteenth ACM Conference on Data and Application Security and Privacy, Charlotte, NC, USA, April 24 - 26, 2023 (pp. 15-26). ACM Digital Library
Open this publication in new window or tab >>IdDecoder: A Face Embedding Inversion Tool and its Privacy and Security Implications on Facial Recognition Systems
2023 (English)In: Proceedings of the Thirteenth ACM Conference on Data and Application Security and Privacy, ACM Digital Library, 2023, p. 15-26Conference paper, Published paper (Refereed)
Abstract [en]

Most state-of-the-art facial recognition systems (FRS:s) use face embeddings. In this paper, we present the IdDecoder framework, capable of effectively synthesizing realistic-neutralized face images from face embeddings, and two effective attacks on state-of-the-art facial recognition models using embeddings. The first attack is a black-box version of a model inversion attack that allows the attacker to reconstruct a realistic face image that is both visually and numerically (as determined by the FRS:s) recognized as the same identity as the original face used to create a given face embedding. This attack raises significant privacy concerns regarding the membership of the gallery dataset of these systems and highlights the importance of both the people designing and deploying FRS:s paying greater attention to the protection of the face embeddings than currently done. The second attack is a novel attack that performs the model inversion, so to instead create the face of an alternative identity that is visually different from the original identity but has close identity distance (ensuring that it is recognized as being of the same identity). This attack increases the attacked system's false acceptance rate and raises significant security concerns. Finally, we use IdDecoder to visualize, evaluate, and provide insights into differences between three state-of-the-art facial embedding models.

Place, publisher, year, edition, pages
ACM Digital Library, 2023
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-199091 (URN)10.1145/3577923.3583645 (DOI)2-s2.0-85158107585 (Scopus ID)9798400700675 (ISBN)
Conference
CODASPY '23: Thirteenth ACM Conference on Data and Application Security and Privacy, Charlotte, NC, USA, April 24 - 26, 2023
Available from: 2023-11-11 Created: 2023-11-11 Last updated: 2023-11-16Bibliographically approved
Carlsson, N. & Eager, D. L. (2023). Optimized Dynamic Cache Instantiation and Accurate LRU Approximations under Time-varying Request Volume. IEEE Transactions on Cloud Computing, 11(1), 779-797
Open this publication in new window or tab >>Optimized Dynamic Cache Instantiation and Accurate LRU Approximations under Time-varying Request Volume
2023 (English)In: IEEE Transactions on Cloud Computing, ISSN 2168-7161, Vol. 11, no 1, p. 779-797Article in journal (Refereed) Published
Abstract [en]

Content-delivery applications can achieve scalability and reduce wide-area network traffic using geographically distributed caches. However, each deployed cache has an associated cost, and under time-varying request rates (e.g., a daily cycle) there may be long periods when the request rate from the local region is not high enough to justify this cost. Cloud computing offers a solution to problems of this kind, by supporting dynamic allocation and release of resources. In this paper, we analyze the potential benefits from dynamically instantiating caches using resources from cloud service providers. We develop novel analytic caching models that accommodate time-varying request rates, transient behavior as a cache fills following instantiation, and selective cache insertion policies. Within the context of a simple cost model, we then develop bounds and compare policies with optimized parameter selections to obtain insights into key cost/performance tradeoffs. We find that dynamic cache instantiation can provide substantial cost reductions, that potential reductions strongly dependent on the object popularity skew, and that selective cache insertion can be even more beneficial in this context than with conventional edge caches. Finally, our contributions also include accurate and easy-to-compute approximations that are shown applicable to LRU caches under time-varying workloads.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2023
Keywords
Costs; Cloud computing; Measurement; Transient analysis; Context modeling; Computational modeling; Analytical models; edge cloud; dynamic cache instantiation; time-varying request volumes; selective cache insertion; request count window
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-188890 (URN)10.1109/tcc.2021.3115959 (DOI)000965223500001 ()
Funder
Swedish Research Council
Note

Funding: Swedish Research Council; Natural Sciences and Engineering Research Council (NSERC) of Canada

Available from: 2022-09-29 Created: 2022-09-29 Last updated: 2023-11-11
Hasselquist, D., Kihlberg Gawell, E., Karlström, A. & Carlsson, N. (2023). Phishing in Style: Characterizing Phishing Websites in the Wild. In: Proc. Network Traffic Measurement and Analysis Conference (TMA): . Paper presented at Proc. Network Traffic Measurement and Analysis Conference (TMA), Napoli, Italy, 26-29 June, 2023. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Phishing in Style: Characterizing Phishing Websites in the Wild
2023 (English)In: Proc. Network Traffic Measurement and Analysis Conference (TMA), Institute of Electrical and Electronics Engineers (IEEE), 2023Conference paper, Published paper (Refereed)
Abstract [en]

The prevalence of phishing domains is steadily rising as attackers exploit toolkits to create phishing websites. As web development expertise is no longer a prerequisite, phishing attacks have become more widespread, outpacing many existing detection methods. Developing novel techniques to identify malicious domains is crucial to safeguard potential victims online. While most current methods emphasize the visual aspects of phishing websites, in this paper, we investigate the underlying structure by collecting data on style sheets and certificates from both verified phishing domains and benign domains. Using a token-based similarity algorithm, we group the phishing domains into three categories and identify shared characteristics of these domains. Our work demonstrates the feasibility of using structural similarities to identify a website created using a phishing kit. By employing such detection, users would be able to browse the web with a reduced risk of falling victim to malicious activities.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2023
Series
2023 7th Network Traffic Measurement and Analysis Conference (TMA)
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-199092 (URN)10.23919/TMA58422.2023.10199059 (DOI)2-s2.0-85168760335 (Scopus ID)9783903176584 (ISBN)9798350325676 (ISBN)
Conference
Proc. Network Traffic Measurement and Analysis Conference (TMA), Napoli, Italy, 26-29 June, 2023
Available from: 2023-11-11 Created: 2023-11-11 Last updated: 2023-11-16Bibliographically approved
Säfvenberg, R., Carlsson, N. & Lambrix, P. (2023). Simple and Practical Goal Importance Metrics for Ice Hockey. In: Tim Brecht, Niklas Carlsson, Mikael Vernblom, Patrick Lambrix (Ed.), Proceedings of the Linköping Hockey Analytics Conference LINHAC 2023 Research Track: . Paper presented at Linköping Hockey Analytics Conference LINHAC 2023, June 7-9, 2023 (pp. 40-52). Linköping, Sweden: Linköping University Electronic Press
Open this publication in new window or tab >>Simple and Practical Goal Importance Metrics for Ice Hockey
2023 (English)In: Proceedings of the Linköping Hockey Analytics Conference LINHAC 2023 Research Track / [ed] Tim Brecht, Niklas Carlsson, Mikael Vernblom, Patrick Lambrix, Linköping, Sweden: Linköping University Electronic Press, 2023, p. 40-52Conference paper, Published paper (Refereed)
Abstract [en]

To capture that not all goals are of the same importance, a new performance metric called the Game Points Importance Value (GPIV) was recently proposed. While this metric takes into account the expected impact that a goal has on the outcome of a game based on the context when the goal was scored, it relies on a relatively fine-grained state space. To address this problem, this paper presents simplified and more practical variations of the GPIV metric. Motivated by our analysis of the relative importance of different dimensions of the state space, we present two metrics that capture the most important component(s) of GPIV. Our evaluation shows that the metrics are relatively stable and capture most of the relative differences between GPIV and traditional metrics (e.g., goals, assist, points, and +/-). These results suggest that these simple and practical metrics are intuitive, capture most of the desirable variations that GPIV captures, and that the value of a goal can be well estimated using GPIV data based on historic data.

Place, publisher, year, edition, pages
Linköping, Sweden: Linköping University Electronic Press, 2023
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 201
Keywords
Sports Analytics, Ice hockey analytics
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-197745 (URN)10.3384/ecp201.4 (DOI)
Conference
Linköping Hockey Analytics Conference LINHAC 2023, June 7-9, 2023
Available from: 2023-09-12 Created: 2023-09-12 Last updated: 2023-09-22Bibliographically approved
Le, M. H. & Carlsson, N. (2023). StyleID: Identity Disentanglement for Anonymizing Faces. Paper presented at Will also be presented at the Privacy Enhancing Technologies Symposium (PETS) July 2023.. Proceedings on Privacy Enhancing Technologies (PoPETs)
Open this publication in new window or tab >>StyleID: Identity Disentanglement for Anonymizing Faces
2023 (English)In: Proceedings on Privacy Enhancing Technologies (PoPETs)Article in journal (Refereed) Accepted
Abstract [en]

Privacy of machine learning models is one of the remaining challenges that hinder the broad adoption of Artificial Intelligent (AI). This paper considers this problem in the context of image datasets containing faces. Anonymization of such datasets is becoming increasingly important due to their central role in the training of autonomous cars, for example, and the vast amount of data generated by surveillance systems. While most prior work de-identifies facial images by modifying identity features in pixel space, we instead project the image onto the latent space of a Generative Adversarial Network (GAN) model, find the features that provide the biggest identity disentanglement, and then manipulate these features in latent space, pixel space, or both. The main contribution of the paper is the design of a feature-preserving anonymization framework, StyleID, which protects the individuals’ identity, while preserving as many characteristics of the original faces in the image dataset as possible. As part of the contribution, we present a novel disentanglement metric, three complementing disentanglement methods, and new insights into identity disentanglement. StyleID provides tunable privacy, has low computational complexity, and is shown to outperform current state-of-the-art solutions.

National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-188914 (URN)
Conference
Will also be presented at the Privacy Enhancing Technologies Symposium (PETS) July 2023.
Funder
Wallenberg AI, Autonomous Systems and Software Program (WASP)
Note

This work is accepted and will soon be published open access.  We are still waiting for doi etc.  

Available from: 2022-09-30 Created: 2022-09-30 Last updated: 2023-04-03
Säfvenberg, R., Svarén, M., Carlsson, N. & Lambrix, P. (2023). The Importance of Special Teams in Ice Hockey. In: Tim Brecht, Niklas Carlsson, Mikael Vernblom, Patrick Lambrix (Ed.), Proceedings of the Linköping Hockey Analytics Conference LINHAC 2023 Research Track: . Paper presented at Linköping Hockey Analytics Conference LINHAC 2023, June 7-9, 2023 (pp. 53-65). Linköping, Sweden: Linköping University Electronic Press
Open this publication in new window or tab >>The Importance of Special Teams in Ice Hockey
2023 (English)In: Proceedings of the Linköping Hockey Analytics Conference LINHAC 2023 Research Track / [ed] Tim Brecht, Niklas Carlsson, Mikael Vernblom, Patrick Lambrix, Linköping, Sweden: Linköping University Electronic Press, 2023, p. 53-65Conference paper, Published paper (Refereed)
Abstract [en]

This paper explores the significance of special teams, particularly powerplay, in ice hockey. Despite the commonly held perception of their importance, little research has examined the impact of powerplay and penalty kill performance on overall team success. The paper uses several seasons of NHL data to characterize goal-scoring and manpower opportunities, and perform analysis from several perspectives. The results indicate that individual even strength goals and powerplay goals have similar value, but the larger share of even strength goals scored over a season makes even strength play a more important contributor to team success. The paper also finds a high correlation between teams that perform above/below average during even strength and powerplay. This study provides insights into the dynamics of ice hockey gameplay and the role of special teams in determining team success.

Place, publisher, year, edition, pages
Linköping, Sweden: Linköping University Electronic Press, 2023
Series
Linköping Electronic Conference Proceedings, ISSN 1650-3686, E-ISSN 1650-3740 ; 201
Keywords
Sports Analytics, Ice hockey analytics
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-197747 (URN)10.3384/ecp201.5 (DOI)
Conference
Linköping Hockey Analytics Conference LINHAC 2023, June 7-9, 2023
Available from: 2023-09-12 Created: 2023-09-12 Last updated: 2023-09-22Bibliographically approved
Jarpehult, O., Josefsson Ågren, F., Bäckström, M., Hallonqvist, L. & Carlsson, N. (2022). A Longitudinal Characterization of the Third-Party Authentication Landscape. In: 2022 IFIP Networking Conference (IFIP Networking): . Paper presented at IFIP Networking Conference (IFIP Networking), Catania, ITALY, jun 13-16, 2022. IEEE
Open this publication in new window or tab >>A Longitudinal Characterization of the Third-Party Authentication Landscape
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2022 (English)In: 2022 IFIP Networking Conference (IFIP Networking), IEEE , 2022Conference paper, Published paper (Refereed)
Abstract [en]

Many websites offer users to authenticate using third-party identity providers (IDPs) such as Facebook or Google. As part of the signup process, these websites often ask the user to give them additional permissions with the IDP (e.g., some data sharing or authorize some actions) that can have significant privacy implications. Motivated by the increased scrutiny of Facebook and other popular IDPs (e.g., due to the 2018 Cambridge Analytica scandal), we present a longitudinal analysis of the IDP usage and permissions changes over the past nine years (2012–2021) as well as a large-scale characterization of the current state. Our longitudinal analysis identifies trends and characterizes changes in both the IDP usage and permission agreements of different subsets of websites. For our large-scale analysis, we develop and share a Selenium-based measurement framework that we use to collect datasets. Using this data, we study the IDP usage across popularity ranges, the permissions used in the wild, and highlight differences between websites using different IDPs and those that do not. Our analysis shows increased IDP usage, especially among the most popular websites, and that the permission requests on average are becoming more modest but also brings forward significant exceptions that may need further scrutiny.

Place, publisher, year, edition, pages
IEEE, 2022
National Category
Computer Sciences
Identifiers
urn:nbn:se:liu:diva-188888 (URN)10.23919/IFIPNetworking55013.2022.9829804 (DOI)000855528800043 ()9783903176485 (ISBN)
Conference
IFIP Networking Conference (IFIP Networking), Catania, ITALY, jun 13-16, 2022
Available from: 2022-09-29 Created: 2022-09-29 Last updated: 2022-11-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1367-1594

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