A survey on peer-to-peer video streaming systems

Video-over-IP applications have recently attracted a large number of users on the Internet. Traditional client-server based video streaming solutions incur expensive bandwidth provision cost on the server. Peer-to-Peer (P2P) networking is a new paradigm to build distributed network applications. Recently, several P2P streaming systems have been deployed to provide live and on-demand video streaming services on the Internet at low server cost. In this paper, we provide a survey on the existing P2P solutions for live and on-demand video streaming. Representative P2P streaming systems, including tree, multi-tree and mesh based systems are introduced. We describe the challenges and solutions of providing live and on-demand video streaming in P2P environment. Open research issues on P2P video streaming are also discussed.

High-Speed Dynamic Packet Filtering

One problem encountered while monitoring gigabit networks, is the need to filter only those packets that are interesting for a given task while ignoring the others. Popular packet filtering technologies enable users to specify complex filters but do not usually allow multiple filters to be specified. This paper describes the design and implementation of a new dynamic packet filtering solution that allows users to specify several IP filters simultaneously with almost no packet loss even on highly-loaded gigabit links. The advantage is that modern traffic monitoring applications such as P2P, IPTV, and VoIP, monitoring and lawful interception can dynamically set packet filters to efficiently discard packets into the operating system kernel according to traffic, calls, and users being monitored.

P2P Object-based adaptivE Multimedia Streaming (POEMS)

Peer-to-peer (P2P) paradigm has recently gained tremendous attraction and is widely used for content distribution and sharing. The future multimedia communication applications have to support the user’s needs, the terminal capabilities, the content specification and the underlying networking technologies. They should be network-aware, topology-aware, and end-user-centric. Thus, in this paper, we use the characteristics of the object-based encoding scheme and P2P network topology to propose adaptive content delivery architecture for P2P networks. We propose an efficient mechanism for transmission of real-time content over P2P networks, called POEMS (P2P Object-based adaptivE Multimedia Streaming). This object-based audio-visual quality adaptive mechanism over P2P networks is media-aware, network-aware, and user-centric that is carried-out through (1) selection of appropriate sending peers willing to participate in the streaming mechanism, (2) organization of sending peers by constructing an overlay network to facilitate content delivery and adaptation, (3) dynamicity management of peers when some peer enters or leaves the system to maintain an acceptable level of perceived video quality, and (4) ensuring the end-to-end QoS (Quality of Services) by orchestrating the overall streaming mechanism. The obtained results demonstrate that combining content adaptation using object-based encoding and advance network-aware peers selection based on peer monitoring leads to intelligent, efficient, and large-scale support of multimedia services over complex network architectures.

P-chaining: a practical VoD service scheme autonomically handling interactive operations

Providing scalable VoD streaming services has recently become a hot issue, and many approaches have been proposed. Because video streaming services through the Internet are widely used, the need to support VCR operations also increases. However, there are few approaches to supporting VCR operations on the Internet. We propose a service scheme based on chaining, in which clients as well as the server provide streaming services. In the proposed scheme, services are provided by unicast and managed locally using node lists. In addition, our scheme can support frequent VCR operations without incurring significant overhead in the server workload. We have evaluated our scheme through simulation with real traces from a content distribution network (CDN) company and with various parameters. The results show that the proposed scheme reduces server workload significantly. The results also verify that frequent VCR operations can be served smoothly without causing too much overhead.

Connecting the family with awareness systems

Awareness systems have attracted significant research interest for their potential to support interpersonal relationships. Investigations of awareness systems for the domestic environment have suggested that such systems can help individuals stay in touch with dear friends or family and provide affective benefits to their users. Our research provides empirical evidence to refine and substantiate such suggestions. We report our experience with designing and evaluating the ASTRA awareness system, for connecting households and mobile family members. We introduce the concept of connectedness and its measurement through the Affective Benefits and Costs of communication questionnaire (ABC-Q). We inform results that testify the benefits of sharing experiences at the moment they happen without interrupting potential receivers. Finally, we document the role that lightweight, picture-based communication can play in the range of communication media available.

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On string languages generated by spiking neural P systems with exhaustive use of rules

We continue the study of (extended) spiking neural P systems with exhaustive use of rules by considering these computing devices as language generators. Specifically, a step is associated with a symbol according to the number of spikes emitted by the output neuron and the sequence of these symbols associated with a halting computation constitutes a string. Two cases are considered: one of them interprets a step when no spike is emitted as a specified symbol, the other interprets such a step as the empty string. In both cases, it is proved that finite and recursively enumerable languages are characterized by extended spiking neural P systems working in the exhaustive mode. The relationships with regular languages are also investigated.

Automatically wrapping legacy software into services: A grid case study

The computational grid is rapidly evolving into a service-oriented computing infrastructure that facilitates resource sharing for solving large-scale data and computationally intensive problems. Peer-to-peer (P2P) systems have emerged as an infrastructure enabling technologies for enhanced scalability and reliability in file sharing and content distribution. It is envisioned that P2P enabled service-oriented grid systems would virtualize various resources as services with high scalability and reliability. Many legacy software resources exist nowadays, but making them grid aware services for effective resource sharing has become an issue of vital importance. This paper presents GSLab, a toolkit for automatically wrapping legacy software into services that can be published, discovered and reused in grid environments. GSLab employs Sun Grid Engine (SGE) to enhance its performance in execution of wrapped services. Using GSLab, we have automatically wrapped a legacy computer animation rendering code written in C as a service that can be discovered and accessed in a SGE environment. The evaluation results show that the performance of GSLab improves with an increase in the number of computing nodes involved.

The 2007 IEEE CEC simulated car racing competition

This paper describes the simulated car racing competition that was arranged as part of the 2007 IEEE Congress on Evolutionary Computation. Both the game that was used as the domain for the competition, the controllers submitted as entries to the competition and its results are presented. With this paper, we hope to provide some insight into the efficacy of various computational intelligence methods on a well-defined game task, as well as an example of one way of running a competition. In the process, we provide a set of reference results for those who wish to use the simplerace game to benchmark their own algorithms. The paper is co-authored by the organizers and participants of the competition.

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Multicast video-on-demand service in an enterprise network with client-assisted patching

Multicast Video-on-Demand (VoD) systems are scalable and  cheap-to-operate. In such systems, a single stream is shared by a batch of common user requests. In this research, we propose multicast communication technique in an Enterprise Network where multimedia data are stored in distributed servers. We consider a novel patching scheme called Client-Assisted Patching where clients’ buffer of a multicast group can be used to patch the missing portion of the clients who will request the same movie shortly. This scheme significantly reduces the server load without requiring larger client cache space than conventional patching schemes. Clients can join an existing multicast session without waiting for the next available server stream which reduces service latency. Moreover, the system is more scalable and cost effective than similar existing systems. Our simulation experiment confirms all these claims.

Subscriber mobility management for a P2P publish/subscribe overlay in mobile tactical networks

P2P (Peer-to-Peer) overlay is a promising distributed computing and communication paradigm that allows for a group of participants to share information and coordinate their resources. Dissemination of information among end users can also be greatly facilitated by the publish/subscribe model. In this paper, we employ the publish/subscribe model in a P2P mobile tactical networking environment. Considering the particular requirements for mobile tactical networks, we investigate the problem of subscriber mobility management and propose a novel proactive handoff approach for improved system responsiveness and reliability. A comprehensive performance evaluation of the proposed mechanism is presented. The obtained results demonstrate significant performance benefits of the proposed scheme.

Scientific models and ethical issues in hybrid bionic systems research

Research on hybrid bionic systems (HBSs) is still in its infancy but promising results have already been achieved in laboratories. Experiments on humans and animals show that artificial devices can be controlled by neural signals. These results suggest that HBS technologies can be employed to restore sensorimotor functionalities in disabled and elderly people. At the same time, HBS research raises ethical concerns related to possible exogenous and endogenous limitations to human autonomy and freedom. The analysis of these concerns requires reflecting on the availability of scientific models accounting for key aspects of sensorimotor coordination and plastic adaptation mechanisms in the brain.

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Methods for quantitative usability requirements: a case study on the development of the user interface of a mobile phone

Quantitative usability requirements are a critical but challenging, and hence an often neglected aspect of a usability engineering process. A case study is described where quantitative usability requirements played a key role in the development of a new user interface of a mobile phone. Within the practical constraints of the project, existing methods for determining usability requirements and evaluating the extent to which these are met, could not be applied as such, therefore tailored methods had to be developed. These methods and their applications are discussed.

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P2Cast: peer-to-peer patching for video on demand service

Providing video on demand (VoD) service over the Internet in a scalable way is a challenging problem. In this paper, we propose P2Cast—an architecture that uses a peer-to-peer approach to cooperatively stream video using patching techniques, while only relying on unicast connections among peers. We address the following two key technical issues in P2Cast: (1) constructing an application overlay appropriate for streaming; and (2) providing continuous stream playback (without glitches) in the face of disruption from an early departing client. Our simulation experiments show that P2Cast can serve many more clients than traditional client-server unicast service, and that it generally out-performs multicast-based patching if clients can cache more than 10% of a stream’s initial portion. We handle disruptions by delaying the start of playback and applying the shifted forwarding technique. The threshold in P2Cast, i.e., the length of time during which arriving clients form a single session, can serve as a “knob” to adjust the balance between the scalability and the clients’ viewing quality.

Insensitive Traffic Models for Communication Networks

We present a survey of traffic models for communication networks whose key performance indicators like blocking probability and mean delay are independent of all traffic characteristics beyond the traffic intensity. This insensitivity property, which follows from that of the underlying queuing networks, is key to the derivation of simple and robust engineering rules like the Erlang formula in telephone networks.

LuxTrace: indoor positioning using building illumination

Tracking location is challenging due to the numerous constraints of practical systems including, but not limited to global cost, device volume and weight, scalability and accuracy; these constraints are typically more severe for systems that should be wearable and used indoors. We investigate the use of wearable solar cells to track changing light conditions (a concept that we named LuxTrace) as a source of user displacement and activity data. We evaluate constraints of this approach and present results from an experimental validation of displacement and activity estimation. The results indicate that a distance estimation accuracy of 21 cm (80% quantile) can be achieved. A simple method to combine LuxTrace with complementary absolute location estimation methods is also presented. We apply carpet-like distributed RFID tags to demonstrate online learning of new lighting environments.

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IPBGA: a hybrid P2P based grid architecture by using information pool protocol

The current representatives of Grid systems are Globus and Web services, however, they have poor scalability and single point failure. It is these two factors which make the building of an improved P2P and grid hybrid framework for resource management and task schedule such a popular research topic. This paper differs from current research because it puts forward an Information Pool Based Grid Architecture (IPBGA), which is a real sense hybrid of P2P and grid instead of only introducing P2P methods into grid systems for resource management. Based on virtualizations, abstract physical resources and tasks to be, the information requests from resources for tasks and appeals from tasks for resources are upgraded as information services by using an information pool protocol (IPP). Thus, grid resource management and task scheduling are regarded as information matching by IPP which is adaptive to the heterogeneous, dynamic, and distributed characteristics of a grid system. Tri-Information Center (Tri-IC) and source ranking mechanisms are presented in IPP to improve robustness, prevent sybil attack, and to discourage free riding. Experiments and theory analysis show that the IPP of the IPBGA is more efficient and robust in dealing with information while both the bandwidth and process costs are less.

Dynamic and context-aware streaming adaptation to smooth quality degradation due to IEEE 802.11 performance anomaly

The need for application-level context visibility to properly perform streaming service management in wired-wireless integrated networks is widely recognized. In particular, the paper claims the need for full application-level awareness of context data about the IEEE 802.11 performance anomaly, i.e., when even a single node located at the borders of the coverage area of a Wi-Fi access point produces a relevant degradation in the connectivity quality of all other nodes in the area. We propose a middleware that on the one hand portably predicts and detects anomaly situations via decentralized and lightweight client-side mechanisms and, on the other hand, exploits anomaly awareness to promptly react with application-level management operations (streaming quality downscaling and traffic shaping). In particular, the paper focuses on how our middleware performs anomaly-driven quality downscaling both to preserve the goodput at nodes in well-covered areas and to minimize quality degradations at the clients generating the anomaly. The reported experimental results point out how anomaly prediction/detection can relevantly improve the effectiveness of streaming downscaling, thus allowing to maintain acceptable service quality notwithstanding Wi-Fi anomaly occurrences.

ONTRACK: Dynamically adapting music playback to support navigation

Listening to music on personal, digital devices whilst mobile is an enjoyable, everyday activity. We explore a scheme for exploiting this practice to immerse listeners in navigation cues. Our prototype, ONTRACK, continuously adapts audio, modifying the spatial balance and volume to lead listeners to their target destination. First we report on an initial lab-based evaluation that demonstrated the approach’s efficacy: users were able to complete tasks within a reasonable time and their subjective feedback was positive. Encouraged by these results we constructed a handheld prototype. Here, we discuss this implementation and the results of field-trials. These indicate that even with a low-fidelity realisation of the concept, users can quite effectively navigate complicated routes.

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Multimodal support to group dynamics

The complexity of group dynamics occurring in small group interactions often hinders the performance of teams. The availability of rich multimodal information about what is going on during the meeting makes it possible to explore the possibility of providing support to dysfunctional teams from facilitation to training sessions addressing both the individuals and the group as a whole. A necessary step in this direction is that of capturing and understanding group dynamics. In this paper, we discuss a particular scenario, in which meeting participants receive multimedia feedback on their relational behaviour, as a first step towards increasing self-awareness. We describe the background and the motivation for a coding scheme for annotating meeting recordings partially inspired by the Bales’ Interaction Process Analysis. This coding scheme was aimed at identifying suitable observable behavioural sequences. The study is complemented with an experimental investigation on the acceptability of such a service.

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Interacting with mobile services: an evaluation of camera-phones and visual tags

We present a study of using camera-phones and visual-tags to access mobile services. Firstly, a user-experience study is described in which participants were both observed learning to interact with a prototype mobile service and interviewed about their experiences. Secondly, a pointing-device task is presented in which quantitative data was gathered regarding the speed and accuracy with which participants aimed and clicked on visual-tags using camera-phones. We found that participants’ attitudes to visual-tag-based applications were broadly positive, although they had several important reservations about camera-phone technology more generally. Data from our pointing-device task demonstrated that novice users were able to aim and click on visual-tags quickly (well under 3 s per pointing-device trial on average) and accurately (almost all meeting our defined speed/accuracy tradeoff of 6% error-rate). Based on our findings, design lessons for camera-phone and visual-tag applications are presented.

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