Abstract: Many activities on the web are driven by high-level goals of users, such as “plan a trip” or “buy some product”. In this paper, we are interested in exploring the role and structure of users’ goals in web search. We want to gain insights into how users express goals, and how their goals can be represented in a semi-formal way. This paper presents results from an exploratory study that focused on analyzing selected search sessions from a search engine log. In a detailed example, we demonstrate how goal-oriented search can be represented and understood as a traversal of goal graphs. Finally, we provide some ideas on how to construct large-scale goal graphs in a semi-algorithmic, collaborative way. We conclude with a description of a series of challenges that we consider to be important for future research.

Abstract: An approach for quality-of-service based replica management in a proxy-to-proxy network is presented. Management decisions are based on a metrics called replication affinity. Replication affinity combines two other affinity metrics we call (1) placement affinity and (2) reallocation affinity. Placement affinity is used to find the best location to enable QoS based media delivery to future clients. Reallocation affinity is used to make media stream replacement decisions in case of insufficient storage space. Using our approach content replacements can be varied in the granularity. Granularity variations are possible for compressed videos by using multiple description coding (MDC). The effect of using replication affinity is evaluated by emulation experiments. For the experiments the network simulator NS-2 has been used.

Abstract: Active and passive replication are powerful techniques to improve the quality of multimedia streaming. Most systems follow either the active or the passive approach. A well known example for active replication are Content Distribution Networks [8] that replicate data to predefined static locations. In contrast to that, P2P file sharing networks [2, 1] use passive replication where identical content is usually provided by different peers. We suggest a system that combines both techniques using Proxy Affinity, Request Affinity and Replication Affinity considering user preferences, user behaviour, hardware resources and networks capabilities.

Abstract: With the advent of Web 2.0 technologies a new attitude towards processing contents in the Internet has emerged. Nowadays it is a lot easier to create, share and retrieve multimedia contents on the Web. However, with the increasing amount in contents retrieval becomes more challenging and often leads to inadequate search results. One main reason is that image clustering and retrieval approaches usually stick either solely to the images' low-level features or their user-generated tags (high-level features). However, this is frequently inappropriate since the "real" semantics of an image can only be derived from the combination of low-level and high-level features. Consequently, we investigated a more holistic view on image semantics based on a system called Imagesemantics. This system combines MPEG-7 descriptions for low-level content-based retrieval features and MPEG-7 keywords by a machine learning approach producing joined OWL rules. The rule base is used in Imagesemantics to improve retrieval results.

Abstract: Due to the increasing performance requirements of decoding H.264/AVC in HDTV or larger resolutions, new approaches are necessary to enable real-time processing. According to the current trend to parallel computation in all performance classes, decoding of AVC must be mapped to these architectures even though this is complicated by the increased complexity and many data dependencies in the codec. We propose and evaluate different ways of using multithreading to speed-up our .NET implemented decoder. While slice based approaches scale best, this is not a flexible approach because of the reliance on specially encoded streams. Functional partitioning and macroblock pipelining prove to be a good alternative for almost all evaluated videos.

Abstract: While there is a lot of hype around various concepts associated with the term Web 2.0 in industry, little academic research has so far been conducted on the implications of this new approach for the domain of education. Much of what goes by the name of Web 2.0 can, in fact, be regarded as new kinds of learning technologies, and can be utilised as such. This paper explains the background of Web 2.0, investigates the implications for knowledge transfer in general, and then discusses its particular use in eLearning contexts with the help of short scenarios. The main challenge in the future will be to maintain essential Web 2.0 attributes, such as trust, openness, voluntariness and self-organisation, when applying Web 2.0 tools in institutional contexts.

Abstract: Time- or history-management systems are implemented in a lot of existing applications. The visited web pages in browsers, the undoing list in nearly every editor or the recorded differences in version control systems are only some examples where time-based information plays an important role. Every kind of information (no matter if we talk about the last headlines in the newspaper or the last user inputs on the workstation) without an explicit date description is nearly useless. Due this fact we are wondering why no global time axis for recording general time-based information is integrated in today’s operating systems. We will introduce a time model to record all kinds of user actions and general time-based events as well. As a second part we will analyze how the visual output system can profit from such a global time axis as well. Up to now it takes a great effort to implement animated user interfaces and so they are rarely found on today’s software market. With the global conjunction of time it is possible to generate animations automatically for every kind of information. We explore the ways of using the time dimension for information presentation (for timely and not timely information as well). We will evaluate these so-called 4D user interfaces1 and introduce a programming model to take advantage of the time-dimension in multiple ways.

Abstract: The visualization of temporal information should not be seen as a special case. A lot of applications take already advantage of the time factor (e.g. capturing user events) but nearly all of them implement this feature completely proprietary. So why do we not embed the time as a ”first class citizen” in today’s operating systems that every application can use time based operations in an unified way. Such an invention would not only improve and standardize the capturing of temporal events but it would be of benefit for a temporal visualization system too. Within a 3D visualization space and a global time axis we introduce a printf4D() 1 method. With this method it is possible to display images, videos, text strings or any other kinds of information in an automatically animated way. As a first proposal we demonstrate this function in a ”flow of information” metaphor where information-objects are not displayed all at once but in a flowing manner over a certain period of time. Additionally we will show that printf4D() is not limited to temporal data. It can be extended automatically to any kind of static information.

Abstract: Is Web 2.0 just hype or just a buzzword, which might disappear in the near future One way to find answers to these questions is to investigate the actual benefit of the Web 2.0 for real use cases. Within this contribution we study a very special aspect of the Web 2.0 the folksonomy and its use within self-directed learning. Guided by conceptual principles of emergent computing we point out methods, which might be able to let semantics emerge from folksonomies and discuss the effect of the results in self-directed learning.

Abstract: Folksonomies, collaboratively created sets of metadata, are becoming more and more important for organising information and knowledge of communites in the Web. While for a single user the difference to keyword assignment is marginal, the power of folksonomies emerges from the collaborative aspects. Folksonomies are already issue of research.Within this publication we analyse underlying statistical properties of broad folksonomies aiming to identify laws and characteristics, which allow inferring properties for folksonomy based retrieval. The actual benefit of folksonomies for retrieval and the derived methods are concluded from experiments with aggregated data from del.icio.us1.

Abstract: The evaluation of retrieval mechanisms for inter-method comparison is necessary in academic as well as in applied research. A major issue in every evaluation is in which way and to what extent the actual perception of the user from the target user group is integrated. Within multimedia retrieval systems the impressions and perceptions of users vary much more than in text retrieval. Empirical studies are a common tool in social science and offer a way to research the correlation between the user perception and the computed similarity between pairs of multimedia documents or a query and the set of results. This approach can be used to complement and extend current evaluation approaches. Within this contribution we summarize general methods from social science and psychology for the interested reader in the area of computer science with some knowledge about statistics. Furthermore we give two examples of undertaken empirical experiments and their outcomes. Within the first one the perception of users is investigated and compared to factors like background and gender, while in the second study metrics are tested upon their ability to reflect the notion of similarity of users. Both experiments aim to give examples and insight on how empirical studies can be used in multimedia research in general and multimedia retrieval evaluation in special.

Abstract: There is a number of image retrieval systems which allow a fast similarity search in large image databases. But to our knowledge there are no image retrieval systems which bring together information extraction from the image as well as object recognition and classification of the object analyzed. This paper introduces techniques to enable the extraction of botanical characteristics from visual features to support semi-automatic plant recognition. The identification of plants requires recognition and determination of plant species specific features such as bloom colour, inflorescences, shape of blooms, number of petals and shape of leaves. Our approach is to improve an existing medicinal plant database, called MedPhyt, by this basic requirement. We demonstrate the first steps towards a semiautomatic system for the identification of a plant species or at least plant families by the combination of both bloom colour and contour information under consideration of a specific content and knowledge domain using the features of MPEG-7.

Abstract: The increasing diversity of devices and the heterogeneity of networks pose nowadays a challenge in the delivery and consumption of multimedia content. In this context, the Part 7 of the MPEG-21 standard formally named Digital Item Adaptation (DIA) targets the adaptation of multimedia content based on usage environment, such as network characteristics, terminal capabilities and user characteristics. But, MPEG-21 DIA does not take into account MPEG-7 semantics description tools, which provide means for a conceptual (semantic) description that is close to the human understanding of multimedia content. Therefore, to fill this gap, we proposed and implemented an interactive and user-centric framework called Semantic Adaptation Framework (SAF). The SAF provides facilities for the generation of all the required semantic metadata and enables an MPEG-21 adaptation engine to semantically adapt the multimedia content in order to provide the user with the best possible experience.

Abstract: Daten zu Daten werden Metadaten genannt. Sie ermöglichen die effektive Organisation, Administration und Suche nach Daten aller Arten. Demgegenüber erlaufebn Ontologen die Formalisierung der Fakten und die detailgenaue Beschreibung von Domänenwissen. In vielen Anwendungsbereichen haben sich die klassischen Metadatenformate als zu einfach und Ontologien als zu komplex erwiesen, was zu neuen Formaten führte. Hier wird ein gemeinsames Modell für solche Formate vorgestellt, das sich zur Datensuche eignet.

Abstract: High level metadata provides a way to manage, organize and retrieve multimedia data based on the actual content using content descriptions. The MPEG-7 Semantic Description Scheme provides tools for storing expressive and interpretable high level metadata. As it is currently impossible for computers to create high level metadata autonomously, users have to create the annotations manually. Generally the manual annotation of multimedia content is understood as laborious and complex task. Within this publication we assess the complexity of the annotation task for the MPEG-7 Semantic Description Scheme within a small user evaluation and the results of the evaluation are discussed.

Abstract: The paper in hand presents an adoption of the suffix tree model for the retrieval of labeled graphs. The suffix tree model encodes path information of graphs in an efficient way and so reduces the size of the data structures compared to path index based approaches, while offering a better runtime performance than subgraph isomorphism based methods. Within a specific use case we evaluate the correlation of the developed method to human judgement and compare the correlation values to other methods. We show that in our use case, which is the retrieval of digital photos annotated with MPEG-7 using the MPEG-7 Semantic Description Scheme, the presented algorithm performs better than other methods.

Abstract: The year 2005 was a successful year for the MPEG and Multimedia Metadata Community. The community was founded within a first workshop in March 2005 in Klagenfurt, Austria, initiated and organized by Harald Kosch. A second workshop, which took place at the I-Know 05, the International Conference for Knowledge Management 2005 in Graz, Austria, was organized by Mathias Lux and Michael Granitzer to enlarge the community and to plan future joint activities. With a third workshop at the RWTH Aachen, Germany, organized by Marc Spaniol and Ralf Klamma, the community grew further, aims of the community were clarified and the schedule for 2006 was developed. Within the three workshops a lot of topics and projects have been discussed. The JUKM special issue on the MPEG and Multimedia Metadata Community Workshop Results 2005 aims to distribute results of community discussions and projects of the community members. The contributions to this issue have been presented by at least one of the authors at one of the above mentioned workshops. The discussion of the community has been integrated and a scientific paper has been generated. The publication has then been peer reviewed by community members. Two different types of contributions have been accepted. Technical notes are smaller in size, but present valuable partial results of ongoing research. Full papers provide more in depth discussion of applications and approaches as well as results and conclusions. From the various presentations of the three workshops in 2005 six topics have been selected for publication, whereas only the last contribution is not a full paper but a technical note.