| 1. |
- de Leng, Daniel, 1988-, et al.
(författare)
-
Second Screen Journey to the Cup: Twitter Dynamics during the Stanley Cup Playoffs
- 2018
-
Ingår i: Proceedings of the 2nd Network Traffic Measurement and Analysis Conference (TMA). - 9783903176096 - 9781538671528 ; , s. 1-8
-
Konferensbidrag (refereegranskat)abstract
- With Twitter and other microblogging services, users can easily express their opinion and ideas in short text messages. A recent trend is that users use the real-time property of these services to share their opinions and thoughts as events unfold on TV or in the real world. In the context of TV broadcasts, Twitter (over a mobile device, for example) is referred to as a second screen. This paper presents the first characterization of the second screen usage over the playoffs of a major sports league. We present both temporal and spatial analysis of the Twitter usage during the end of the National Hockey League (NHL) regular season and the 2015 Stanley Cup playoffs. Our analysis provides insights into the usage patterns over the full 72-day period and with regards to in-game events such as goals, but also with regards to geographic biases. Quantifying these biases and the significance of specific events, we then discuss and provide insights into how the playoff dynamics may impact advertisers and third-party developers that try to provide increased personalization.
|
|
| 2. |
- Holmstrom, Jesper, et al.
(författare)
-
Do we Read what we Share? Analyzing the Click Dynamic of News Articles Shared on Twitter
- 2019
-
Ingår i: PROCEEDINGS OF THE 2019 IEEE/ACM INTERNATIONAL CONFERENCE ON ADVANCES IN SOCIAL NETWORKS ANALYSIS AND MINING (ASONAM 2019). - New York, NY, USA : Institute of Electrical and Electronics Engineers (IEEE). - 9781450368681 ; , s. 420-425
-
Konferensbidrag (refereegranskat)abstract
- News and information spread over social media can have big impact on thoughts, beliefs, and opinions. It is therefore important to understand the sharing dynamics on these forums. However, most studies trying to capture these dynamics rely only on Twitters open APIs to measure how frequently articles are shared/retweeted, and therefore do not capture how many users actually read the articles linked in these tweets. To address this problem, in this paper, we first develop a novel measurement methodology, which combines the Twitter steaming API, the Bitly API, and careful sample rate selection to simultaneously collect and analyze the timeline of both the number of retweets and clicks generated by news article links. Second, we present a temporal analysis of the news cycle based on five-day-long traces (containing both clicks and retweet over time) for the news article links discovered during a seven-day period. Among other things, our analysis highlights differences in the relative timelines observed for clicks and retweets (e.g., retweet data often lags and underestimates the bias towards reading popular links/articles), and helps answer important questions regarding differences in how age-based biases and churn affect how frequently news articles shared on Twitter are accessed over time.
|
|
| 3. |
- Keskisärkkä, Robin, 1987-, et al.
(författare)
-
An Ontology for Ice Hockey
- 2019
-
Ingår i: ISWC 2019 Satellites. ; , s. 13-16
-
Konferensbidrag (refereegranskat)abstract
- Ice hockey is a highly popular sport that has seen significant increase in the use of sport analytics. To aid in such analytics, most major leagues collect and share increasing amounts of play-by-play data and other statistics. Additionally, some websites specialize in making such data available to the public in user-friendly forms. However, these sites fail to capture the semantic information of the data, and cannot be used to support more complex data requirements. In this paper, we present the design and development of an ice hockey ontology that provides improved knowledge representation, enables intelligent search and information acquisition, and helps when using information from multiple databases. Our ontology is substantially larger than previous ice hockey ontologies (that cover only a small part of the domain) and provides a formal and explicit representation of the ice hockey domain, supports information retrieval, data reuse, and complex performance metrics.
|
|
| 4. |
- Krishnamoorthi, Vengatanathan, 1987-
(författare)
-
Efficient HTTP-based Adaptive Streaming of Linear and Interactive Videos
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Online video streaming has gained tremendous popularity over recent years and currently constitutes the majority of Internet traffic. As large-scale on-demand streaming continues to gain popularity, several important questions and challenges remain unanswered. This thesis addresses open questions in the areas of efficient content delivery for HTTP-based Adaptive Streaming (HAS) from different perspectives (client, network and content provider) and in the design, implementation, and evaluation of interactive streaming applications over HAS.As streaming usage scales and new streaming services emerge, continuous improvements are required to both the infrastructure and the techniques used to deliver high-quality streams. In the context of Content Delivery Network (CDN) nodes or proxies, this thesis investigates the interaction between HAS clients and proxy caches. In particular, we propose and evaluate classes of content-aware and collaborative policies that take advantage of information that is already available, or share information among elements in the delivery chain, where all involved parties can benefit. Asides from the users’ playback experience, it is also important for content providers to minimize users’ startup times. We have designed and evaluated different classes of client-side policies that can prefetch data from the videos that the users are most likely to watch next, without negatively affecting the currently watched video. To help network providers to monitor and ensure that their customers enjoy good playback experiences, we have proposed and evaluated techniques that can be used to estimate clients’ current buffer conditions. Since several services today stream over HTTPS, our solution is adapted to predict client buffer conditions by only observing encrypted network-level traffic. Our solution allows the operator to identify clients with low-buffer conditions and implement policies that help avoid playback stalls.The emergence of HAS as the de facto standard for delivering streaming content also opens the door to use it to deliver the next generation of streaming services, such as various forms of interactive services. This class of services is gaining popularity and is expected to be the next big thing in entertainment. For the area of interactive streaming, this thesis proposes, models, designs, and evaluates novel streaming applications such as interactive branched videos and multi-video stream bundles. For these applications, we design and evaluate careful prefetching policies that provides seamless playback (without stalls or switching delay) even when interactive branched video viewers defer their choices to the last possible moment and when users switches between alternative streams within multi-video stream bundles. Using optimization frameworks, we design and implement effective buffer management techniques for seamless playback experiences and evaluate several tradeoffs using our policies.
|
|
| 5. |
- Lindskog, Eric, et al.
(författare)
-
Generalized Playback Bar for Interactive Branched Video
- 2019
-
Ingår i: PROCEEDINGS OF THE 27TH ACM INTERNATIONAL CONFERENCE ON MULTIMEDIA (MM19). - New York, NY, USA : ASSOC COMPUTING MACHINERY. - 9781450368896 ; , s. 2369-2377
-
Konferensbidrag (refereegranskat)abstract
- During viewing of interactive branched video, users are asked to make viewing choices that impact the storyline of the video playback. This type of video puts the users in control of their viewing experiences and provides content creators with great flexibility how to personalize the viewing experience of individual viewers. However, in contrast to with traditional video, where the use of a playback bar is default for most - if not all - players, there currently does not exist any generic playback bar for branched video that helps visualize the upcoming branch choices. Instead, most branched video implementations are typically custom-made on a per-video basis (e.g., see custom-made Netflix and BBC movies) and do not use a playback bar. As an important step towards addressing this void, we present the first branched video player with a generalized playback bar that visualizes the tree-like video structure and the buffer levels of the different branches. The player is implemented in dash.js and is made public with this publication, is the first of its kind, and allows both the playback bar and the presentation of branch choices to be customized with regards to visual appearance, functionality, and the content itself. Furthermore, the design is generic (making it applicable to any video) and allows content creators to easily create large numbers of branched movies using a simple metafile format. Finally, and most importantly, we perform a three-phase user study in which we evaluate the playback bar, compare with alternative designs, and other branch-related features. The user study highlights the value of a branched video playback bar, and provides interesting insights into how it and other design customization features may best be integrated into a player.
|
|
| 6. |
- Ljung, Dennis, et al.
(författare)
-
Player Pairs Valuation in Ice Hockey
- 2019
-
Ingår i: Proceedings of the 5th Workshop on Machine Learning and Data Mining for Sports Analytics. - Cham : Springer. - 9783030172732 - 9783030172749 ; , s. 82-92
-
Konferensbidrag (refereegranskat)abstract
- To overcome the shortcomings of simple metrics for evaluating player performance, recent works have introduced more advanced metrics that take into account the context of the players’ actions and perform look-ahead. However, as ice hockey is a team sport, knowing about individual ratings is not enough and coaches want to identify players that play particularly well together. In this paper we therefore extend earlier work for evaluating the performance of players to the related problem of evaluating the performance of player pairs. We experiment with data from seven NHL seasons, discuss the top pairs, and present analyses and insights based on both the absolute and relative ice time together.
|
|
| 7. |
- Nsolo, Edward, 1988-, et al.
(författare)
-
Player Valuation in European Football
- 2019
-
Ingår i: Proceedings of the 5th Workshop on Machine Learning and Data Mining for Sports Analytics. - Cham : Springer. - 9783030172732 - 9783030172749 ; , s. 42-54
-
Konferensbidrag (refereegranskat)abstract
- As the success of a team depends on the performance of individual players, the valuation of player performance has become an important research topic. In this paper, we compare and contrast which attributes and skills best predict the success of individual players in their positions in five European top football leagues. Further, we evaluate different machine learning algorithms regarding prediction performance. Our results highlight features distinguishing top-tier players and show that prediction performance is higher for forwards than for other positions, suggesting that equally good prediction of defensive players may require more advanced metrics.
|
|
| 8. |
- Nykvist, Carl, et al.
(författare)
-
Server-Side Adoption of Certificate Transparency
- 2018
-
Ingår i: Passive and Active Measurement. - Cham : Springer. - 9783319764801 - 9783319764818 ; , s. 186-199
-
Konferensbidrag (refereegranskat)abstract
- Certificate Transparency (CT) was developed to mitigate shortcomings in the TLS/SSL landscape and to assess the trustworthiness of Certificate Authorities (CAs) and the certificates they create. With CT, certificates should be logged in public, audible, append-only CT logs and servers should provide clients (browsers) evidence, in the form of Signed Certificate Timestamps (SCTs), that the certificates that they present have been logged in credible CT logs. These SCTs can be delivered using three different methods: (i) X.509v3 extension, (ii) TLS extension, and (iii) OSCP stapling. In this paper, we develop a client-side measurement tool that implements all three methods and use the tool to analyze the SCT adoption among the one-million most popular web domains. Using two snapshots (from May and Oct. 2017), we answer a wide range of questions related to the delivery choices made by different domains, identify differences in the certificates used by these domains, the CT logs they use, and characterize the overheads and potential performance impact of the SCT delivery methods. By highlighting some of the tradeoffs between the methods and differences in the websites selecting them, we provide insights into the current SCT adoption status and differences in how domains have gone upon adopting this new technology.
|
|
| 9. |
- Sans Fuentes, Carles, et al.
(författare)
-
Player impact measures for scoring in ice hockey
- 2019
-
Ingår i: Proceedings of MathSport International 2019 Conference. - Athen : Athens University of Economics and Business. ; , s. 307-317
-
Konferensbidrag (refereegranskat)abstract
- A commonly used method to evaluate player performance is to attribute values to the different actions that players perform and sum up these values every time a player performs these actions. In ice hockey, such metrics include the number of goals, assists, points, plus-minus statistics and recently Corsi and Fenwick. However, these metrics do not capture the context of player actions and the impact they have on the outcome of later actions. Therefore, recent works have introduced more advanced metrics that take into account the context of the actions and perform look-ahead. The use of look-ahead is particularly valuable in low-scoring sports such as ice hockey. In this paper, we first extend a recent approach based on reinforcement learning for measuring a player's impact on a team's scoring. Second, using NHL play-by-play data for several regular seasons, we analyze and compare these and other traditional measures of player impact. Third, we introduce notions of streaks and show that these may provide information about good players, but do not provide a good predictor for the impact that a player will have the next game. Finally, streaks are compared for different player categories, highlighting differences between player positions and correlations with player salaries.
|
|
