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MUM Tables of Contents: 0405060708091011121314

Proceedings of the 2008 International Conference on Mobile and Ubiquitous Multimedia

Fullname:Proceedings of the 7th International Conference on Mobile and Ubiquitous Multimedia
Editors:Mikael Wiberg; Arkady Zaslavsky; Mikael Wiberg
Location:Umea, Sweden
Dates:2008-Dec-03 to 2008-Dec-05
Standard No:ISBN: 978-1-60558-192-7; ACM DL: Table of Contents; hcibib: MUM08
Links:Conference Website
  1. Ubiquitous interaction, ubiquitous multimedia
  2. Smart multimedia applications and services
  3. Sharing and managing multimedia in heterogeneous networks
  4. Mobile and ubiquitous applications -- 1
  5. Industrial session -- papers with industry focus
  6. Context-aware multimedia applications and services
  7. User-centric mobile multimedia
  8. Mobile and ubiquitous applications -- 2
  9. Wireless multimedia networking
  10. Keynotes

Ubiquitous interaction, ubiquitous multimedia

Leveraging social networking services to encourage interaction in public spaces BIBAFull-Text 2-7
  Simo Hosio; Hannu Kukka; Jukka Riekki
The breakthrough of web 2.0 and sudden uprising of hundreds of different social networking sites have modified the way we communicate and share our experiences and lives with other people. Despite the undeniable networking advantages this digital world offers, it cannot be seen as purely positive development. Due to a prospering online "hang around" culture, we have lost genuine rich human social experiences to some degree. This paper proposes how to utilize the digital identities and content people have created within these services to improve and encourage natural communication and lower the social barrier of natural interaction in public settings. We propose a system that combines the content in the virtual world with the presence in real world settings. SocS (Social Surroundings) brings out digital information and media content of users to the current physical space, thus attempting to make individuals more approachable by other participants. The requirements, design principles and design of the proposed application are presented. We also discuss the usage and current state of social networking sites as a motivator for new genre of intelligent services.
Designing multi-user multi-device systems: an architecture for multi-browsing applications BIBAFull-Text 8-14
  Yun Ding; Jochen Huber
As users get accustomed to an increasing diverse range of mobile devices, personal computers, intelligent home and office appliances, as well as shared public devices, collaborative multi-device systems are emerging to benefit from using together devices of different users and different capabilities. This paper presents a conceptual framework for the systematic design of such systems in symbiotic environments. It distinguishes between information and interaction spaces. Focusing on using devices together, we introduce relationships between interaction spaces and annotatable mappings between the information space and the interaction spaces. Customizable annotations and the corresponding transformation of information support the development of collaborative systems for different scenarios. To demonstrate the validity of our framework, we introduce an architecture for multi-device web-browsing systems, and an annotation vocabulary which particularly focuses on symbiotic environments. The evaluation of our implemented prototype confirms the usefulness of multi-browsing, and the need for supporting both developers and end users to individually annotate web pages.
Environment interaction: character, challenges & implications for design BIBAFull-Text 15-22
  Mikael Wiberg; Erik Stolterman
With the current development towards completely interactive environments realized through ubiquitous computing technologies and new transmaterials, the interaction landscape is changing from consisting of separated computer environments and related human-computer interaction issues, to being more about interactive architecture and human- (digitally enhanced) environment interaction. Given this general shift it becomes important to examine the fundamental challenges, consequences, and implications for design facing interaction designers. In this paper we therefore set out to: 1) describe the general character of these future interactive environments, 2) discuss interaction design challenges related to fully interactive environments, and 3) point at some general implications for design given this new understanding. To exemplify this trend, we describe two ongoing research projects that illustrate some aspects of the changes of the physical environment and changes in the (traditional) relation between the physical environment and its habitants. Finally, we present some arguments for environment interaction theorizing as a fundamental approach to tackle this general and fundamental challenge for the field of human-computer interaction.
Exploring personal broadcast channels for rich media sharing in close relationships BIBAFull-Text 23-30
  Natasa Milic-Frayling; Martin Hicks; Rachel Jones; Jamie Costello
Building on the Internet (IP) platforms available on mobile devices and personal computers (PCs), we implemented a service called weConnect that facilitates broadcast of content via dedicated and personal media channels. weConnect includes simple tools for integrating content into media 'mixes' and provides 'content viewers' for ubiquitous access to weConnect channels via mobile, desktop, and other IP enabled devices. In this paper we present an exploratory user study based on deployment of the weConnect service among individuals in close relationships. The study focuses on the user perception and experience with the 'always-on' channels, delivering personalized content. We started with images, text, and animations as familiar and easily accessible media. We observed a high level of reciprocity in creating and exchanging expressive content and a need for persistence, reuse, and notification of content delivery. The users voiced their enthusiasm for receiving personalized media across mobile and desktop devices. The always-on nature of the weConnect channels raised new requirements for the service design to assist content producers with creating streams of personalized media efficiently and to enable recipients to view the content flexibly.

Smart multimedia applications and services

AQUAM: automatic query formulation architecture for mobile applications BIBAFull-Text 32-39
  Fotis Menemenis; Symeon Papadopoulos; Ben Bratu; Simon Waddington; Yiannis Kompatsiaris
When a user performs a web search, the first query entered will frequently not return the required information. Thus, one needs to review the initial set of links and then to modify the query or construct a new one. This incremental process is particularly frustrating and difficult to manage for a mobile user due to the device limitations (e.g. keyboard, display). We present a query formulation architecture that employs the notion of context in order to automatically construct queries, where context refers to the article currently being viewed by the user. The proposed system uses semantic metadata extracted from the web page being consumed to automatically generate candidate queries. Novel methods are proposed to create and validate candidate queries. Further two variants of query expansion and a post-expansion validation technique are described. Finally, insights into the effectiveness of our system are provided based on evaluation tests of its individual components.
Benchmark of middleware protocols for application and service interaction BIBAFull-Text 40-47
  Pekka Pääkkönen; Daniel Pakkala
A variety of protocols exist, which may be considered as messaging middleware for facilitating application and service interactions in distributed and technologically heterogeneous environments. Standardized candidates include text-based Simple Object Access Protocol (SOAP) of Web Services (WS) and Instant Messaging Extensions of the Session Initiation Protocol (SIP). In addition, binary-based approaches such as Generic Communications Middleware (GCM) and compression of XML have been proposed. The contribution of this paper is a benchmark and evaluation of SOAP, SIP and GCM as messaging middleware for application and service interaction. In particular protocol overhead, Round-Trip-Time (RTT) and processing latency have been focused on in experiments performed in a Java-based test-bed. The results indicate the optimized performance of the binary approaches, when compared to text-based protocols. More importantly the detailed performance comparison indicates factors contributing to RTT and processing latency, which should be helpful when making technology selections between the protocol candidates. In addition applicability of the protocols is discussed.
Evaluating AI planning for service composition in smart environments BIBAFull-Text 48-55
  Florian Marquardt; Adelinde M. Uhrmacher
Smart environments are characterized by dynamic ensembles of devices that offer individual services to the user in an unobtrusive manner. For more advanced services often the cooperation of devices is required which can be accomplished by composition of services. To keep the composition process as unobtrusive as possible it must be fast and resource saving. AI planning is one possibility to realize service composition. Four different planners have been evaluated referring to execution time. The evaluation has been based on an abstract simulation model that reflects some key characteristics of services in smart environments, e.g. number of services and distribution of pre- and postconditions of these services. The evaluation results showed that planners like UCPOP, SGP, and particularly blackbox, are suitable for composing services in time in a typical smart environment. However, their run time behavior is irregular and additionally differ with respect to how fast they recognize that no plan exist. These cases require specific strategies to avoid unnecessary resource consumption.

Sharing and managing multimedia in heterogeneous networks

Touch & Share: RFID based ubiquitous file containers BIBAFull-Text 57-63
  Iván Sánchez; Jukka Riekki; Jarkko Rousu; Susanna Pirttikangas
Here, we present Touch & Share, an application for sharing multimedia content in our everyday environment. Our main design criterion is ease of use. Visual icons placed in the environment act as data storage (file containers). Users can drop multimedia files into the containers and pick files from them by touching the icons with their mobile terminals. The icons are placed on, or near, the physical objects the files are related to. RFID tags are placed behind the icons and they store metadata information about the files available in the corresponding containers. When users bring their terminals near the icons, the terminals' RFID readers communicate with the tags, read the contents of a container from the tag and possibly write information about new files. The actual files are stored in a server, but the user experiences the files to be in the containers. The main contributions of this work are a general application for storing multimedia content in nearly any place or everyday object and a fully functional prototype built using only commercial off-the-self technology.
Evaluation of multimedia services in mobile WiMAX BIBAFull-Text 64-70
  Bruno Sousa; Kostas Pentikousis; Marilia Curado
Mobile WiMAX defines an architecture for metropolitan area broadband wireless access networks based on IEEE 802.16e. One of the most important characteristics of WiMAX is support of applications with different QoS requirements in terms of delay, jitter and bandwidth. We briefly review IEEE 802.16 and the mobile WiMAX network reference model and discuss how IEEE 802.21 can enhance mobility management. Mobile WiMAX is often cited as an important 4G contender. We evaluate via simulation its capacity to support real time applications in high-speed vehicular scenarios and assess the potential of using cross-layer information made available by IEEE 802.21/MIH. Our results indicate that using MIH information allows for the fulfillment of multimedia application requirements. On the other hand, the requirements of such applications are far from being fulfilled when MIH assistant information is not employed.
A policy-based framework for autonomic reconfiguration management in heterogeneous networks BIBAFull-Text 71-78
  Zhenzhen Zhao; Jie Chen; Noel Crespi
This paper presents a policy-based framework to approach the issue of autonomous reconfiguration management in heterogeneous networks. In contrast to existing policy-based approaches, the proposed framework addresses the management issue from a new perspective through posing it as a problem of learning from current network behavior, while creating and updating policies dynamically in response to changing reconfiguration requirements, and this task is implemented by Reinforcement Learning methodology. A two-layer policy model is used to mapping users and operators' higher level goals into network level objectives. The autonomic reconfiguration procedures for policy creation, storage, evaluation are also presented in detail. Illustrative examples analysis and simulation results demonstrate the performance of the proposed work.

Mobile and ubiquitous applications -- 1

panOULU Luotsi: a location based information mash-up with XML aggregator and WiFi positioning BIBAFull-Text 80-83
  Hannu Kukka; Timo Ojala; Juha Tiensyrjä; Teemu Mikkonen
We introduce panOULU Luotsi, a multi-device location-based information mash-up provided for the users of a large municipal wireless network. XML content in various forms, such as RSS/ATOM feeds from several content providers are automatically merged into a database using a flexible XML aggregator. It allows mapping different heterogeneous information feeds into the database without any changes to the application source code. The location of the user is estimated by identifying the WiFi access point to which the user's wireless device is currently connected. The information relevant to the user's current location is imposed on a map for a location-based browsing view, which allows the user to learn about nearby services, sites and events of interest.
Augmented assembly using a mobile phone BIBAFull-Text 84-87
  Mark Billinghurst; Mika Hakkarainen; Charles Woodward
In this paper we present a mobile phone based augmented reality (AR) assembly system that enables users to view complex models on their mobile phones. It is based on a client/server architecture, where complex model information is located on a PC, and a camera phone is used as a thin client access device to augment still images of the assembly site with animated AR sequences.
Smart environments meet the semantic web BIBAFull-Text 88-91
  Christiane Reisse; Christoph Burghardt; Florian Marquardt; Thomas Kirste; Adelinde Uhrmacher
Smart Environments are designed to proactively assist their users. One way to achieve this is by composing sequences of potential user actions and of devices' actions at run time. This requires the actions to be specified in a declarative manner. A favorable formalism for declarative descriptions are semantic web services. In this paper, we describe our approach to proactive assistance in smart environments and explain how semantic web services can be employed as the basic building blocks for such an environment. We provide a state-of-the-art review of existing semantic web service technologies and discuss how they should be enhanced to suit our needs.
Experimental evaluation of read performance for RFID-based mobile sensor data gathering applications BIBAFull-Text 92-95
  Iain A. Currie; Mahesh K. Marina
We consider RFID-based sensing applications enabled by passive or semi-passive tags and mobile devices equipped with readers. We experimentally investigate the feasibility of such RFID-based mobile sensor data gathering applications, focusing on UHF RFID devices and indoor scenarios. We examine the impact of various factors, including reader mobility, multiple closely located tags and other key related metrics. Our measurement results suggest the feasibility of using RFID for such applications.

Industrial session -- papers with industry focus

A crawling and ranking method for improving context-awareness in mobile web search BIBAFull-Text 97-100
  José Manuel Cantera; Guido García Bernardo; Jorge Cabrero Alonso
There are still many web sites that are unaware of mobile presentation and, when accessed from handheld devices, offer a poor user experience. In this paper we present both an adaptive content crawling and a ranking method that enable to measure the suitability of a web page against a target device and web browser. Our proposed techniques could be used by context-aware mobile web search engines, ranking pages not only from the textual relevancy point of view, but also from its adaptability to the delivery context. Our experimental results reveal high accuracy for the devised method.
Where would you bring your laptop?: live blogging in an outdoors mechanical shop BIBAFull-Text 101-104
  Stina Nylander
We describe the blogging habits of 19 teams of students participating in the KTH triennial carnival. They were blogging in a rough environment, i.e. outdoors while nailing or welding carnival carriages together and painting them, and they were interviewed on site. Astonishingly enough, students did not mind bringing laptops into this environment. 53% of the postings made during the study were made from the construction site. The ability to blog from the site seemed to be important, teams that blogged from the site blogged more that teams who did not.
Autonomic composition of ubiquitous multimedia applications in REACHES BIBAFull-Text 105-108
  Oleg Davidyuk; Iván Sánchez; Jon Imanol Duran; Jukka Riekki
In this paper, we describe our work in developing an autonomic system that supports the composition of ubiquitous applications at run-time. The applications are composed and adapted accordingly to user preferences and user-provided criteria. We have designed a proof-of-concept prototype of the system and an example multimedia application. The application is a multimedia player which users can control on a large screen using the mobile phone's UI as the controller. We present a user evaluation of the prototype's feasibility and also determine what feedback and control mechanisms are required by the end-users. We report initial analysis of how user satisfaction and comfort level are affected by the autonomy of the system.
Obtaining resource controllability in service cooperation environments BIBAFull-Text 109-112
  Shudong Chen; Johan Lukkien
In a ubiquitous computing environment, devices host services that are accessed by anonymous users. This causes threats of resource abuse through malicious attacks or resource scarcity through unintentional excessive service invocations. In this paper, the secure resource control for service sharing is presented which depends on two basic functionalities: access control and soft-state management. Services are grouped into virtual communities for secure access. Service cooperation through external orchestration can only be done within a virtual community. Services can be activated/deactivated by a device management service running on their host devices. Real-time resource utilization of services for virtual community applications is monitored. Therefore, resources on a shared device can be protected from malicious use and become controllable for special quality of service provisioning.
A case study of real-world testing BIBAFull-Text 113-116
  Birgitta Bergvall-Kåreborn; Staffan Larsson
In this paper we present the results of a real-world test of a mobile application for public transportation, as well as lessons learnt by carrying out the test. By this we contribute with experience and accumulated knowledge to the area of mobile applications for public transportation and to the area of real-life testing. Through the test we learnt a number of lessons related to the application, related concepts, people's behavior in relation to public transportation, and last but not least in relation to our method.
A new MIP-SIP interworking scheme BIBAFull-Text 117-120
  Karl Andersson; Muslim Elkotob; Christer Åhlund
This paper proposes a new interworking scheme for Mobile IP and the Session Initiation Protocol being the most popular solutions for mobility management at the network and application layers respectively. The goal is to deliver seamless mobility for both TCP-based and UDP-based applications taking the best features from each mobility management scheme. In short, this paper proposes that TCP connections are handled through Mobile IP while UDP-based connection-less applications may use the Session Initiation Protocol for handling mobility. The two mobility management solutions are integrated into one common solution.

Context-aware multimedia applications and services

Locawe: a novel platform for location-aware multimedia services BIBAFull-Text 122-129
  Mika Luimula; Kari Kuutti
In this paper we present a suggestion for a next generation mobile GIS architecture. The proposed architecture enables to use GIS data also in mobile devices and to handle information received from local sensors. The architecture has been used to design CENTRIA Locawe platform, which has been tested in several field experiments. This platform has been used in various industrial pilots and prototypes, which have proven that Locawe platform can be used efficiently in developing location-aware services for both in outdoor as well as indoor environments.
Semantic maps and mobile context capturing for picture content visualization and management of picture databases BIBAFull-Text 130-136
  Stavros Christodoulakis; Michalis Foukarakis; Lemonia Ragia; Hiroaki Uchiyama; Takuya Imai
Modern cameras are powerful devices that can interoperate using international standards with other sensors that can capture the context of each picture taken. Future cameras are expected to integrate such sensors within them. The contextual parameters captured can be interpreted with the help of semantic maps which are maps that integrate semantic information on them. Semantic maps can be used for understanding and visualization of the picture contents as well as for the management of context and content in picture databases. In this paper, we present a model for the management of semantic image information and the contextual knowledge related to the image capture along with a system implementation that manages and exploits this knowledge. Digital picture contents in the database can be interrelated with, and understood based on, contextual semantic geospatial information that the system manages. We describe the integrated camera system, the calculation and visualization of the contextual parameters, and the management of the semantics of the spatial objects. Finally, we present the implementation of SPIM, a SPatial Image Management system that exploits semantic contextual knowledge, its retrieval functionality and the visual user interfaces.
Towards context-aware face anonymisation BIBAFull-Text 137-144
  Driss Choujaa; Naranker Dulay
Today's high-end mobile phones commonly include one or two digital cameras. These devices, also known as cameraphones, allow their owners to take photographs anywhere, at any time with practically no cost. As a result, many urban dwellers are photographed everyday without even being aware of it. Although in many countries, legislation recognises the right of people to veto the dissemination of their image, snapshots including recognisable passers-by often end up on photo-sharing websites. In this paper, we present a cooperative system for cameraphones which automatically anonymises faces of people photographed involuntarily. Our system, called BlurMe, uses Bluetooth awareness to inform a photographer's cameraphone when people around this photographer do not wish for their picture being taken. It then identifies subjects on the photograph and anonymises other people's faces. BlurMe was tested on 876 face regions detected on 150 real-life photographs collected from a photo-sharing website and manually labelled for subject faces. The system achieved very promising results on photographs with up to three subjects.
Landmark-based pedestrian navigation from collections of geotagged photos BIBAFull-Text 145-152
  Harlan Hile; Ramakrishna Vedantham; Gregory Cuellar; Alan Liu; Natasha Gelfand; Radek Grzeszczuk; Gaetano Borriello
Mobile phones are an attractive platform for landmark-based pedestrian navigation systems. To be practical, such a system must be able to automatically generate lightweight directions that can be displayed on these mobile devices. We present a system that leverages an online collection of geotagged photographs to automatically generate navigational instructions. These are presented to the user as a sequence of images of landmarks augmented with directional instructions. Both the landmark selection and image augmentation are done automatically. We present a user study that indicates these generated directions are beneficial to users and suggest areas for future improvement.

User-centric mobile multimedia

Modeling learning effects in mobile texting BIBAFull-Text 154-161
  Arindam Das; Wolfgang Stuerzlinger
No work on mobile text messaging so far has taken into account the effect of learning on the change in visual exploration behavior as users progress from non-expert to expert level. We discuss within the domain of multi-tap texting on mobile phone and address the process of searching versus selecting a letter on the keypad interface. We develop a simulation model that forecasts the probability of letter location recall by non-expert users and thereby models learning, as the user acquires expertise in recalling, with practice, session after session. We then plugin this probability within a model of visual strategy that combines the effect of different ways visual exploration: non-expert users search for a letter while expert users select a letter. The observed non-expert non-motor time preceding a key press (for a letter) correlates extremely well with the simulation results.
Design guidelines for managing metadata for personal content on mobile devices BIBAFull-Text 162-167
  Tuula Kärkkäinen; Antti Kaakinen; Teija Vainio; Kaisa Väänänen-Vainio-Mattila
Personal media content is increasingly accessed by mobile devices and services. Small handheld devices may give access to thousands of personal media items such as photos, music and messages, but managing the vast amount of content on a small device with a limited user interface (UI) is becoming tedious. Searching content with metadata -- that is, descriptive data about the content -- facilitates locating of particular piece of content. However, in addition to rapidly increasing amount of content, the amount and extent of types of metadata attached to each content object is also growing. Thus, metadata management itself is becoming a burdensome task. We present our study on how to improve metadata management and make it motivating on mobile devices. We conducted 26 interviews and two workshops with users to study users' needs and design requirements for metadata management. As a main result, we present UI design guidelines for personal content related metadata management on mobile devices.
Utilization of pervasive IT compromised?: understanding the adoption and use of a cross media system BIBAFull-Text 168-175
  Katarina Segerståhl
Systems that are extended across multiple media, e.g., a mobile device and a desktop computer, are becoming increasingly popular. One reason for this is their ability to provide pervasive support for human activities across a range of contextual settings. Despite the value that these cross media systems offer, there are aspects that detract from their efficient utilization. This article reports the findings from an empirical case study exploring the adoption and use of a cross media fitness system. The system's general fit with the ways users carry out their activities is a central determinant of utilization. However, the adoption and use of a cross media system is also essentially influenced through the user experience process. This article describes distinct system characteristics that were found to influence coherent user experience. Based on these findings, we propose design responses that address a systemic out of box experience, crossmedial referencing and explication of a holistic system image. This study provides new insight into how users interact with and perceive cross media systems and identifies distinct focus areas for future research and design of heterogeneous and pervasive information technology.

Mobile and ubiquitous applications -- 2

Effects of peer-to-peer overlay parameters on mobile battery duration and resource lookup efficiency BIBAFull-Text 177-180
  Otso Kassinen; Zhonghong Ou; Mika Ylianttila; Erkki Harjula
This paper evaluates the feasibility of mobile nodes as peers in a structured peer-to-peer overlay network. Our performance analysis is based on the Peer-to-Peer Protocol (P2PP), which is a peer protocol candidate for the Peer-to-Peer Session Initiation Protocol (P2PSIP). We use both, live-network measurements and simulations, to evaluate two performance metrics: resource lookup success rate and mobile battery duration. While lookup success rate measures P2PP performance in general, battery duration is crucial for mobile use of P2PP. Restricted battery life limits the feasibility of mobile peers. We reveal the tradeoff between lookup success rate and battery duration. Based on the findings it is possible to find more suitable protocol parameters for mobile peers. The battery duration measurements, made with UDP in UMTS and WLAN access networks, are also applicable in the wireless usage of other application-layer protocols.
Seamless handover for mobile TV over DVB-H applications BIBAFull-Text 181-184
  Lukasz Kondrad; Imed Bouazizi; Moncef Gabbouj
In this paper, we present an approach for achieving application driven seamless handover across different wireless access networks. The target is thereby to eliminate any content loss while minimizing the interruption duration that is perceived by the user during the handover procedure. Ultimately, the user experience will greatly benefit from the usage of the most suitable network access technology. The focus is set on Mobile TV applications, where an ongoing streaming session experiences an application-controlled handover from DVB-H to an alternative unicast access (e.g. Wi-Fi or 3G) or vice versa. A handover decision algorithm is also presented, aiming at enhancing the overall system stability by adjusting to the dynamic conditions of the broadcast channel.
WiMAX backhaul for environmental monitoring BIBAFull-Text 185-188
  Tuomas Nissilä; Kostas Pentikousis; Ilkka Harjula; Jyrki Huusko; Mika Rautio
In environmental monitoring, wirelessly connected sensors form local networks and collect data, which are sent to a central repository for further analysis and permanent storage. In this paper we empirically evaluate the use of fixed WiMAX to backhaul data from an environmental monitoring application. We find that aggregating sensor readings is crucial for taking full advantage of the WiMAX backhaul. We consider application-layer aggregation for scenarios where sensor communication is programmable or at least configurable. For scenarios where sensors cannot be modified, we consider network-layer aggregation using a performance enhancing proxy. Finally, we consider the case where application- and network-layer aggregation are combined. Our results show that without aggregation, goodput is only a small fraction of the maximum achieved in our testbed. Furthermore, we examine the effect of different modulation schemes on performance and quantify in practice the number of wireless sensor nodes that could be served with different modulation and data aggregation combinations.

Wireless multimedia networking

Analysis and measurement of session setup delay and jitter in VoWLAN using composite metrics BIBAFull-Text 190-197
  Muslim Elkotob; Karl Andersson
In this paper we look at the signaling for session mobility using the Session Initiation Protocol (SIP) and the Session Description Protocol (SDP). Bearing in mind that perceived voice quality is sensitive mostly to delay variation (also called jitter), we work on bounding that value for providing a better voice Quality of Service over Wireless LAN (WLAN). For mobility we use a hybrid SIP-MIP stack. The basic idea is to combine the strengths of MIP for doing fast handovers and the strengths of SIP for powerful session adaptation capabilities. Numerical calculation figures as well as real implementation results are provided. It can be observed that the session update cycle during mobility can be modified in such a way that session delay variation bounds achieved are quite low and there are almost no spikes. We use composite performance metrics that we defined in previous work to analyze the correlation between the data patterns for session signaling delay in the classical case and our proposed case to better highlight the achieved performance delta.
Application-aware handover with minimal power consumption for multimedia streaming service in wireless LAN BIBAFull-Text 198-204
  Jong-Tae Park; Jae-Wook Nah; Song Wang
It is a challenging task to provide handover with guaranteed QoS for real-time multimedia service such as VoIP, video/audio streaming, and video conferencing in wireless LAN. This paper is aimed at presenting efficient layer 2 handover mechanism in wireless LAN, which can provide fast handover with guaranteed QoS for real-time multimedia service. In order to meet the above objective, the scanning period and the number of channels per scanning for handover are dynamically adapted to the types of applications and wireless networking environment, so that both the degradation of application service quality and signaling overhead are minimized simultaneously. We simulate proposed mechanism to verify the performance. The simulation results show that the proposed mechanism avoid service quality degradation and provide session connectivity.
A presentation layer mechanism for multimedia playback mobility in service oriented architectures BIBAFull-Text 205-212
  I. Vaishnavi; P. S. Cesar; A. J. Jansen; B. Gao; Dick C. A. Bulterman
This paper presents an approach for media presentation continuity in playback mode. We use the term presentation continuity over session transfer since our solution is at the presentation layer. Previous research on this topic has focused on transferring a particular stream or set of related streams at the sessions layer for live broadcasting or conferencing sessions. We argue that in the realm of service oriented architectures, such as telecom operator networks, this approach does not take full advantage of the particular case of media playback. Our mechanism presents an alternative to the traditional approach, which i) Lowers network control plane overhead, thus reducing chances of presentation consistency loss ii) Lowers network data overhead due to lesser need for transcoding iii) Delegates presentation consistency issues, such as inter-media synchronisation, to the media player iv) Dynamically adapts the presentation to the new target devices without transcoding. Finally, we present experimental results which show that our approach is implementable in acceptable time bounds.


The developer experience BIBAFull-Text 214
  Martin Körling
Over the last few years, there has been a tremendous evolution of hardware and software capabilities of mobile devices and networks. This has opened up for rich user experiences and development of applications and services. Still, there is a big potential for improvement in how application developers can reach mobile users in a simple, rich and controlled way; a potential for improvement of the developer experience. Recent industry initiatives, such as Symbian Foundation, Android, and Apple iPhone, show varying degrees of openness and reach. What makes up a good developer experience? We take a look at technology trends, their impact and challenges.
Architectural knowledge in ubiquitous computing innovation BIBAFull-Text 215
  Rikard Lindgren
After some years of progress in application-centered research, ubiquitous computing has now gained ground in the organizational world. Indeed, organizations are increasingly dependent on assemblages of embedded, mobile, and stationary technologies that innovate business propositions and increase customer value. This talk will focus on the nature and role of architectural knowledge in implementation and use of ubiquitous computing environments. In particular, four dimensions of architectural knowledge will be identified:
  • Technology capability awareness refers to actors' perception of the service
       capability of a specific IT component.
  • Use context sensitivity refers to the understanding of work contexts in which
       a specific IT component is typically deployed.
  • Business model understanding refers to the appreciation of business
       opportunities afforded by applications of a specific IT component.
  • Boundary-spanning competence refers to practical skills and resources for
       engaging in collective efforts to develop architectural knowledge. Drawing on the four dimensions of architectural knowledge, the talk will outline theoretical and strategy implications for development of computing environments capable of serving the goals of heterogeneous actors and technologies. A first implication concerns why different types of architectural configurations promote and/or undermine individual actors' ability to control ubiquitous computing innovation. A second implication concerns how creation of trading zones may allow for actors to meet and negotiate alignment of technologies.