Theo Kanter

Smart Delivery of Multimedia Content for Wireless Applications

Packet-oriented access to cellular networks enables us to deliver multimedia content to mobile users. As cellular networks will continue to deliver circuit switched voice for some time to come, care must be taken to avoid interference between these delivery mechanisms, while maximizing the range of services and the number of users. Smart delivery of multimedia content involving agents running in the mobile, the base station and the content provider allows us to dynamically adapt the application and network behavior to each other in order to meet the criteria for specific applications. In particular, this paper examines the delivery of streaming media and interactive voice as Voice over IP (VoIP) to mobile users. Our conclusion is that this, in combination with the dynamic adaptive properties as introduced by the agents, enables us to transfer voice entirely IP over wireless links, thereby freeing further resources for the new applications that we refer to in this paper.

Attaching context-aware services to moving locations

User information and communication resources - such as precise location information and direction, altitude, light, and humidity measurements (via sensors) - are becoming more available in end devices. This increasing range of information can enable context-aware informational services as well as linking digital objects to physical objects a user is observing. Thus, mobile users can obtain relevant information about real-world objects while simultaneously staying in touch with other users. The author describes an open, scalable service architecture in which context-aware service negotiation lets entities establish communication and negotiate services without a third partys assistance and without advance knowledge of either partys features. Context information can help hide data complexity from users until they need to make choices regarding such things as payments or object interactions.

Distributed context support for ubiquitous mobile awareness services

Context-aware applications and services require ubiquitous access to context information about the users or sensors such as preferences, spatial & environmental data, available connectivity, and device capabilities. Systems for the brokering or the provisioning of context data via wireless networks do so with centralized servers or by employing protocols that do not scale well with real-time distribution capabilities. In other cases, such as the extending of presence systems, the data models are limited in expressive capabilities and consequently incur unnecessary signaling overhead. This paper presents a distributed protocol, the Distributed Context eXchange Protocol (DCXP), and an architecture for the real-time distribution of context information to ubiquitous mobile services: We present the architecture and its principle operation in a sample ubiquitous mobile awareness service. Preliminary results indicate that our approach scales well for the ubiquitous provision of context data in real-time to clients on the Internet via 3G wireless systems. Performed measurements show that DCXP can reduce the time to process context data with a factor of 20 compared to similar approaches.

The MediaSense Framework

Mobile telecommunication is evolving rapidly. People no longer only communicate with each other regardless of time and place, but also share other information that is important for tasks with which they are involved. In response to this growing trend the MediaSense framework addresses the intelligent delivery of any information to any host, anywhere, based on context-aware information regarding personal preferences, presence information, and sensor values. This includes another challenge to achieve seamless delivery, especially of multimedia content, and multimodal services via heterogeneous connections.

Going wireless, enabling an adaptive and extensible environment

This paper discusses limitations in existing and projected solutions for delivering applications to mobile users (e.g., in 3G) in an increasingly diverse heterogeneous wireless infrastructure in combination with the on-going deregulation of mobile communication and with an increasing number of more narrowly defined roles of parties participating in the delivery of applications to mobile users. Furthermore, for future service growth, users need to be the center of communication via applications that take into account the users context or the context of their communication based on any event and not just the invocation or release of communication resources. This calls for entirely rethinking the architectures and frameworks for the delivery of services, in order to create open and scalable support for the negotiation between participating entities with a minimum of a priori and shared knowledge, thus providing an adaptive and extensible environment for user-centric communication. This paper presents a novel architecture and components with these properties and discusses the merits of the approach, followed by a discussion of experimental results demonstrating the feasibility of applying this architecture.

HotTown, enabling context-aware and extensible mobile interactive spaces

This article introduces a novel, open, and scalable service architecture for context-aware personal communication. In contrast to the network-centric open service access in third-generation mobile networks, this architecture moves the point of integration for user services out to the mobile devices, where we can create support for context-aware computing and communication. Support for peer-to-peer service negotiation with minimal a priori shared knowledge, context representation, and reasoning about context enables the mobile agents (that represent users and other entities) to be aware of and react to any event and thus context. Hence, the delivery of context-aware applications to users intertwining digital and physical objects in mobile interactive spaces leverages events from sensors, mobility support, and digital entities. Finally, a presentation of our prototype and experiences from the HotTown project demonstrates the feasibility of the approach and provides some examples of the enabled user communication for large-scale mobile networks.

An open service architecture for adaptive personal mobile communication

Currently, 3GPP is reinventing the telecom model of services in wireless Internet-a model that is not well suited to meet the demands of new modes of personal mobile communication, enabled by wireless packet services and multimedia devices, or the ability to deal with increasingly heterogeneous wireless infrastructure (one interpretation of 4G). This article characterizes the properties of service architectures in relation to the steps taken in successive generations of wireless communication networks for personal communication. The article then continues to present a novel service architecture for open communication in wireless Internet, describing its necessary properties and evaluating its merits. Finally, we present our experiences from building application prototypes based on our service architecture, in an urban wireless testbed consisting of WLAN extensions to a gigabit Ethernet network.

Contextware Research Challenges in Ambient Networks

Network-centric context information is used to make networks more receptive to the users’ needs by personalizing the communication process and making it more sensitive to changes that may occur in the surroundings. As such, it is a natural step that context awareness should be suitably incorporated within traditional networks in order to create an ‘ambient network’. This approach is aimed at enabling the co-operation of heterogeneous networks on demand, transparently to the potential users, and without the need for preconfiguration or offline negotiation between network operators. This paper discusses the approach taken by authors to incorporate context-awareness into ambient networking concepts. It discusses how network-related context information should be utilized in ambient networks for the end user to fully experience the pervasiveness of a network and the research challenges arising from this utilization. The paper also evaluates the benefits of employing context information and contextware concepts in ambient networks.

Event-Driven, Personalizable, Mobile Interactive Spaces

Infrastructure is currently being deployed for delivering multimedia services IP end-to-end. Mobile devices and application resources, because of their computing capabilities, can be enabled with adaptive functionality to shape the services according to the communication conditions and the users context. This raises the question of how events should be managed to create a common awareness of multimedia content and resources in mobile networks. These events can be generated either by the users behavior, movement, availability of (new) mobile resources, or the application server content changes. In this paper, we propose XML-based protocols and agent functionality operating on a distributed tuple-space to accommodate common awareness of these events in applications for mobile users, without the necessity of these events being defined or announced in advance. This facilitates the creation of a new class of personalizable applications in interactive mobile spaces, as demonstrated in our urban wireless test bed.

Enabling Scalable Publish/Subscribe for Logical-Clustering in Crowdsourcing via MediaSense

Crowdsourcing was initially devised as a method for solving problems through soliciting contributions from a large online community. Crowdsourcing is facing new challenges to handle the increase of information in real-time from a vast number of sources in Internet-of-Things (IoT) scenarios. Thus we seek to leverage the power of social web, smart-devices, sensors, etc., fusing these heterogeneous sources into distributed context information in order to enable novel crowdsourcing scenarios. This mandates research in efficient management of heterogeneous and distributed context information through logical-clustering. Logical-clustering can efficiently filter out similar context information obtained from distributed sources based on context similarity. However, the efficiency of logical-clustering is challenged by the distribution of context information in crowdsourcing scenarios. Publish/Subscribe mechanism can counter this challenge. To this end, we propose a scalable publish/subscribe model, MediaSense, which is based on p2p technologies. This paper presents our approach to a scalable logical-clustering concept. The evaluation of our approach applied to MediaSense can achieve a rate of approximately 3530 messages/sec for publish/subscribe events. Moreover, this approach further achieves 99% increase for subscription matching and 163% improvement in memory requirements in comparison with other approaches.