| 1. |
- Bylund, Markus, et al.
(författare)
-
Seamless mobility with personal servers
- 2003. - 1
-
Ingår i: Proceedings of the Stockholm Mobility Roundtable.
-
Konferensbidrag (refereegranskat)abstract
- We describe the concept and the taxonomy of personal servers, and their implications in seamless mobility. Personal servers could offer electronic services independently of network availability or quality, provide a greater flexibility in the choice of user access device, and support the key concept of continuous user experience. We describe the organization of mobile and remote personal servers, define three relevant communication modes, and discuss means for users to exploit seamless services on the personal server.
|
|
| 2. |
- Bylund, Markus, et al.
(författare)
-
Towards Seamless Mobility with Personal Servers
- 2004. - 1
-
Ingår i: Info. - : Emerald. - 1463-6697 .- 1465-9840. ; 6:3, s. 172-179
-
Tidskriftsartikel (refereegranskat)abstract
- Observes that the future of mobile communication networks lies not only in how successful people are in deploying technologies (2.5G or 3G with a high degree of coverage and roaming between operators), but also in how well people can create a functioning environment and usage situation for end-users in which they can get a homogeneous and continuous usage experience, despite the very heterogeneous world in which they, after all, will live. Concepts are advanced that support this observation (network independence, UI/device flexibility, and user experience continuity), and a possible solution is proposed that would take people in that direction (the personal server).
|
|
| 3. |
- Devlic, Alisa, et al.
(författare)
-
Energy consumption reduction via context-aware mobile video pre-fetching
- 2012
-
Ingår i: Proceedings - 2012 IEEE International Symposium on Multimedia, ISM 2012. - : IEEE. - 9780769548753 ; , s. 261-265
-
Konferensbidrag (refereegranskat)abstract
- The arrival of smartphones and tablets, along with a flat rate mobile Internet pricing model have caused increasing adoption of mobile data services. According to recent studies, video has been the main driver of mobile data consumption, having a higher growth rate than any other mobile application. However, streaming a medium/high quality video files can be an issue in a mobile environment where available capacity needs to be shared among a large number of users. Additionally, the energy consumption in mobile devices increases proportionally with the duration of data transfers, which depend on the download data rates achievable by the device. In this respect, adoption of opportunistic content pre-fetching schemes that exploit times and locations with high data rates to deliver content before a user requests it, has the potential to reduce the energy consumption associated with content delivery and improve the user's quality of experience, by allowing playback of pre-stored content with virtually no perceived interruptions or delays. This paper presents a family of opportunistic content pre-fetching schemes and compares their performance to standard on-demand access to content. By adopting a simulation approach on experimental data, collected with monitoring software installed in mobile terminals, we show that content pre-fetching can reduce energy consumption of the mobile devices by up to 30% when compared to the on demand download of the same file, with a time window of 1 hour needed to complete the content prepositioning.
|
|
| 4. |
- Devlic, Alisa, et al.
(författare)
-
Evaluation of energy profiles for mobile video prefetching in generalized stochastic access channels
- 2014
-
Ingår i: Mobile and Ubiquitous Systems: Computing, Networking, and Services. - Cham : Springer. - 9783319115689 ; , s. 209-223
-
Konferensbidrag (refereegranskat)abstract
- This paper evaluates the energy cost reduction of Over-The-Top mobile video content prefetching in various network conditions. Energy cost reduction is achieved by reducing the time needed to download content over the radio interface by prefetching data on higher data rates, compared to the standard on demand download. To simulate various network conditions and user behavior, a stochastic access channel model was built and validated using the actual user traces. By changing the model parameters, the energy cost reduction of prefetching in different channel settings was determined, identifying regions in which prefetching is likely to deliver the largest energy gains. The results demonstrate that the largest gains (up to 70%) can be obtained for data rates with strong correlation and low noise variation. Additionally, based on statistical properties of data rates, such as peak-to-mean and average data rate, prefetching strategy can be devised enabling the highest energy cost reduction that can be obtained using the proposed prefetching scheme.
|
|
| 5. |
- Devlic, Alisa
(författare)
-
On Optimization of Quality of User Experience and Wireless Network Bandwidth in Video Content Delivery
- 2015
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mobile video content today generates more than half of the mobile data traffic.The increasing popularity of mobile video on demand services poses great challenges to mobile operators and content providers. Frontmost, how to reduce the mobile video traffic load, while delivering high quality video content to mobile users without perceived quality degradations for the same (or cheaper) price? Battery lifetime represents another key factor of a user’s Quality of Experience(QoE). A lot of device energy is consumed by mobile network signalling and data transmission over new generation mobile communication systems. This thesis focuses on: (1) reducing the size of the video that is delivered to the enduser in the maximum achievable video quality, thus optimizing the wireless network bandwidth and the user-perceived QoE, and (2) reducing the energy consumption of a mobile device that is associated to data transfer over the radio interface, thus increasing the device’s battery lifetime. The main contributions have been given in providing the Over-the-Top video optimization and delivery schemes and recommendations on tuning their parameters in order to minimize the bandwidth and energy consumption of mobile video delivery, while maximizing the predictable user-perceived QoE. By preventing the video to be prefetched on low data rates and tuning the datarate threshold according to statistical properties of available data rates, we show that 20-70% of energy cost can be reduced by opportunistic prefetching, depending on the user’s pattern of available data rates. The data rate values ordered in time that have a large amount of serial correlation and low noise variance, or low average valueand high peak-to-mean ratio, are likely to yield the highest energy gains from content prefetching. Moreover, we show that energy gains are the largest when the threshold data rate is set close to an average data rate, due to the highest availability of data rates around this value, and for longer sleep time between the prefetching periods, which increases the probability of moving away from the areas with low data rates. Next, we focus on QoE-aware mobile video delivery solutions that are more bandwidth efficient without compromising the user-perceived video quality. They deliver a video over a varying data rate channel that is optimized for viewing on a mobile device in the highest perceptual video quality that can be achieved in the given video and network conditions. An optimized video consists of short segments in the minimum resolutions that satisfy the target perceptual video quality and have up to 60% reduced size compared to the video in the corresponding fixed video resolution, without perceptible quality difference. The delivery is performed by on demand download, context-aware prefetching, or in real time using the QoE-aware adaptive video streaming that runs over Dynamic Adaptive video Streaming over HTTP (DASH). By limiting the maximum bitrates of the requested video segments and using the remaining throughput to prefetch optimized video segments in advance of playout, we show that QoE-aware adaptive video streaming maintains a more stable perceptual video quality than DASH despite the fluctuations of the channel bandwidth, while using fewer number of bits, which improves a user-perceived QoE. The results of this thesis can help operators and content providers to reduce their costs and provide more content to their users at the same (or cheaper) price.
|
|
| 6. |
- Devlic, Alisa, et al.
(författare)
-
QoE-aware optimization for video delivery and storage
- 2015
-
Ingår i: 2015 IEEE 16th International Symposium on "A World of Wireless, Mobile and Multimedia Networks" (WoWMoM) 2015. - Boston, MA, USA. - 9781479984619 ; , s. 1-10
-
Konferensbidrag (refereegranskat)abstract
- The explosive growth of Over-the-top (OTT) online video strains capacity of operators’ networks, which severely threatens video quality perceived by end users. Since video is very bandwidth consuming, its distribution costs are becoming too high to scale with network investments that are required to support the increasing bandwidth demand. Content providers and operators are searching for solutions to reduce this video traffic load, without degrading their customers’ perceived Quality ofExperience (QoE). This paper proposes a method that can programmatically optimize video content for desired QoE accordingto perceptual video quality and device display properties, while achieving bandwidth and storage savings for content providers, operators, and end users. The preliminary results obtained with Samsung Galaxy S3 phone show that up to 60% savings can be achieved by optimizing movies without compromising the perceptible video quality, and up to 70% for perceptible, but not annoying video quality difference. Tailoring video optimization to individual user perception can provide seamless QoE delivery across all users, with a low overhead (i.e., 10%) required to achieve this goal. Finally, two applications of video optimization: QoE-aware delivery and storage, are proposed and examined.
|
|
| 7. |
- Devlic, Alisa, et al.
(författare)
-
Towards QoE-aware adaptive video streaming
- 2016
-
Ingår i: 2015 IEEE 23rd International Symposium on Quality of Service (IWQoS). - : IEEE. - 9781467371131 ; , s. 75-76
-
Konferensbidrag (refereegranskat)abstract
- This paper describes a novel QoE-aware adaptive video streaming method that enhances the viewing experience on mobile devices and reduces cellular network bandwidth consumed by Dynamic Adaptive Streaming over HTTP (DASH) by considering perceptual video quality and data rate channel conditions in the bitrate adaptation process. By streaming an optimized video for the particular video quality and channel conditions toa mobile device, we can improve the worst video qualities causedby DASH streaming and reduce quality variations using fewer number of bits.
|
|
| 8. |
- Dornbush, Sandor, et al.
(författare)
-
XPod: A Human Activity Aware Learning Mobile Music Player
- 2007
-
Ingår i: Proceedings of the Workshop on Ambient Intelligence, 20th International Joint Conference on Artificial Intelligence.
-
Konferensbidrag (refereegranskat)abstract
- The XPod system, presented in this paper, aimsto integrate awareness of human activity and musicalpreferences to produce an adaptive systemthat plays the contextually correct music. TheXPod project introduces a “smart” music playerthat learns its user’s preferences and activity, andtailors its music selections accordingly. We are usinga BodyMedia device that has been shown to accuratelymeasure a user’s physiological state. Thedevice is able to monitor a number of variables todetermine its user’s levels of activity, motion andphysical state so that it may predict what music isappropriate at that point. The XPod user trains theplayer to understand what music is preferred andunder what conditions. After training, the XPod,using various machine-learning techniques, is ableto predict the desirability of a song, given the user’sphysical state.
|
|
| 9. |
|
|
| 10. |
- Jang, Y. M., et al.
(författare)
-
Message from Organizing Chairs
- 2016
-
Ingår i: 8th International Conference on Ubiquitous and Future Networks, ICUFN 2016. - : IEEE Computer Society. - 2165-8528. ; 2016-August
-
Tidskriftsartikel (refereegranskat)
|
|
