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Mobile video service becomes more and more popular with commercial deployment of Long Term Evolution (LTE) networks and other wireless access mechanisms. However, perfect LTE coverage with ubiquitous signal quality is not available in reality. Recently, adaptive HTTP video streaming over LTE has been gaining popularity. The quality of video service faces challenges. In this paper, we study the Quality...
With the prevailing of mobile phones and online video contents, the demand for mobile online video is increasing. The desire, however, is held down by the high mobile traffic cost. To solve this problem, an off-the-shelf solution is WiFi-Direct (WFD), which is widely available on a majority of mobile devices. There is, however, no systematic study of WFD-based group data transfer and cooperative video...
Online video on demand (VoD) service is prevailing. Prediction of user lifespan in a VoD system benefits the service providers to characterize churn risk of users and manage to retain them. A systematical study on this problem is desired but absent in literature. We address this problem based on a large-scale dataset of user watching behavior from PPTV, one of the largest online VoD systems in China...
Some recent work proposed differential private collaborative filtering (DPCF) recommender systems to protect user privacy from indirect access attacks, e.g., KNN attacks. As the cost of such protection, the MAE of recommendation was retained with insignificant increase but the more focused metrics, i.e., the precision and recall of top-k recommendations, degraded unacceptable. To address this problem,...
This paper presents a tracking system based on trajectory matching in WiFi network. When a user equipment appears in the monitored area, the system continuously intercepts WiFi beacon messages which are periodically issued by the user's equipments for finding accessable WiFi access point (AP). The system then infers the user's trajectory based on the MAC address and received signal strength indication...
The rapid development of Video On Demand (VoD) service especially in wireless network incurs huge bandwidth costs. To reduce the bandwidth pressure and improve the user experience, Wireless Service Providers (WSP) began deploy cache in the Mobile Switching Center (MSC) following the power law distribution observation of video popularity for the whole system. However, based on the Sina Video dataset...
A recommendation system learns a user's interests from her historical purchasing or watching behavior, which is disclosed to the recommendation system inevitably. Such a disclosure raises a serious concern in the public for the leak of users' privacy. For instance, a person who watches a lot of videos which are more preferred by women than men can be inferred as female. Recently, as a response to...
Most services present a uniform ranking list according to video popularity in order to satisfy users' potential demands. But recent work claimed that users in video systems showed distinct preferences on popularity of videos. Understanding these preferences has important implications for designing content distribution mechanism and improving recommendation accuracy. Users' Popularity Preferences (PPs)...
Based on a large-scale dataset extracted from the servers' logs of PPTV, one of the largest online video service providers in China, we study how device types, wireless network connection types and video qualities impact user's watching behaviors and network traffic. We found that 1) the diurnal user viewing patterns on mobile devices are slightly different from that on PC devices; 2) the mobile APP's...
In online video systems, viewer demographic information (gender, age, etc.) is of huge commercial value for delivering targeted advertising and video recommendations, but generally not available directly. This paper targets inferring viewers' gender based on implicit watching history in the large-scale online video systems. To tackle the sparsity problem without filtering out any cold users or videos,...
Video watching time is a crucial measure for studying user watching behavior in online Internet video-on-demand (VoD) systems. It is important for system planning, user engagement study, and service quality evaluation. However, due to limited access to large-scale VoD systems, there is still a lack of accurate model for characterizing the distribution of user watching time on a per video basis. In...
Watching ‘on-demand’ video on the Internet is popular. Provider sare paying more attention on mining user behaviour data to improve service quality and attract more loyal users. It is desired to characterize evolution process of user engagement. While there are models characterizing engagement of traditional customers and web users, there still lacks an appropriate metric of user's loyalty for VoD...
In this paper, we measure and study the peer startup process in PPLive, a popular commercial P2P streaming system, and focus on a fundamental issue in this aspect: how a peer initializes its buffer when it joins a channel, i.e., initial offset placement of peers' buffers in the startup stage. We build a general model of peer startup process in chunk-based P2P streaming systems and present an initial...
Video popularity ranking is commonly used in various streaming systems. Existing popularity ranking systems usually rank videos from the perspective of access frequency and ignore other implicit feedback, due to the belief that popularity rankings with different implicit metrics are highly consistent. Based on a large collection of real-world system trace data, this paper systematically compares video...
In a peer-to-peer (P2P) live streaming system, peer requests collide when multiple peers request data pieces from the same peer (or media server). When collisions occur, some of the peers' requests fail and retries have to be taken, which delays peer's receipts of pieces. This paper shows that request collisions occur frequently at both media servers and peers, and have big impact on system performance...
A fundamental problem that a peer-to-peer (P2P) live streaming system faces is how to support flash crowds effectively. A flash crowd occurs when a burst of join requests arrive at a system. When a flash crowd occurs, the sudden arrival of numerous peers may starve the upload capacity of a P2P system, and degrade the quality of service. By theoretical analysis and simulations, we find that a system...
Replication strategy is one of the central design issues in P2P VoD systems. Given the distributed cache spaces of all peers, it aims to address how to utilize them efficiently. In this paper, we concentrate on the essential question for designing: how replication affects the QoS of requests. Unlike the previous works, in order to close to the practice, three types of replicas are differentiated:...
Peer-assisted offline download service provides a new internet content delivery approach, in which the system coordinate dedicated servers and peers to finish a file download. This service has attracted a large number of subscribers. The related research, however, is still missing. This paper presents our preliminary measurement and analysis of users' behavior in QQXuanfeng, one of the most popular...
The Online P2P Video-on-Demand (VOD) streaming system has become one of the most popular Internet applications in recent years. Together with millions of users and tens of millions of workload, comes a big challenge for quality of service. This system's time-free accessing strategy might bring about far more severe access failure than that caused by flash crowds in traditional IPTV. Why does access...
Nowadays, as the fast growth in population of p2p VoD system, user behaviors are playing an increasingly crucial role for the performance of system. In this paper, the user watching and sharing behaviors of p2p VoD system were studied by analyzing a large amount of real data. Then, a comparison between user behavior in p2p VoD system and other main kinds VoD systems was made. After that, a mathematic...
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