Changing user roles in ICT developments; the case of digital television

This paper focuses on the question: what active user roles concerning digital television can be distinguished and how can these be classified in a way they can be related to business models? It will look at the value chain for digital television and try to show where users are enabled to be more active and value adding. The paper will continue with an exploratory look at current interactive television practices. But since interactive television is still in its infancy, to look beyond what is happening in digital and interactive television at this moment, may provide useful insights.     

基于DCT域的MPEG—2视频色度格式转换

提出了一种新的基于DCT域的MPEG-2码流转换算法，该算法与现有算法，即通过解码、空域采样率转换来设定新的码流参数，再编码的算法相比，无需IDCT、DCT操作，便可在DCT域实现码流转换，而且省去了运动矢量估值和运动补偿过程，不仅节省了大量帧存和减少了运算量，而且更具有实时性的优点，对MPEG-2 MP@ML到4：2：2Profile@ML码流转换算法实例的分析和现实表明：该算法能简单有效的实现压缩域码流转换，其思想同样可广泛用于其他基于DCT压缩图象的采样率转换、线性滤波等任务。     

Resolving unwanted couplings through interactive exploration of co-evolving software entities - An experience report

Context

Frequent changes to groups of software entities belonging to different parts of the system may indicate unwanted couplings between those parts. Visualizations of co-changing software entities have been proposed to help developers identify unwanted couplings. Identifying unwanted couplings, however, is only the first step towards an important goal of a software architect: to improve the decomposition of the software system. An in-depth analysis of co-changing entities is needed to understand the underlying reasons for co-changes, and also determine how to resolve the issues.

Objective

In this paper we discuss how interactive visualizations can support the process of analyzing the identified unwanted couplings.

Method

We applied a tool that interactively visualizes software evolution in 10 working sessions with architects and developers of a large embedded software system having a development history of more than a decade.

Results

The participants of the working sessions were overall very positive about their experiences with the interactive visualizations. In 70% of the cases investigated, a decision could be taken on how to resolve the unwanted couplings.

Conclusion

Our experience suggests that interactive visualization not only helps to identify unwanted couplings but it also helps experts to reason about and resolve them.     

Becoming Friends in Online Brand Communities: Evidence From China

With the aid of information technology, consumers have increasingly engaged in social interaction in online brand communities. How can these strangers make friends online? Drawing on embeddedness theory and media richness theory, we examine the antecedents and intermediate mechanisms of online friendship. We theorize that online brand community interactivity aided by instant messaging technology is the main driving force of online friendship, whereas social presence and a sense of yuan (a Chinese concept describing predetermined relations) mediate online friendship development. Online friendship in turn enhances consumer online brand community commitment. We test our conceptual model with a sample of consumers from Chinese online sporting goods forums. The results support our hypotheses and inform online brand community research and practice.     

Interactivity and the Invisible: What Counts as Writing in the Age of Web 2.0

This study asks: what counts as writing in a Web 2.0 environment? How do the vocabularies, functionalities, and organizing structures of Web 2.0 environments impact our understanding of what writing is in these spaces and how that writing is performed? Results suggest that we, as scholars and teachers, need to pay more attention to, first, the interactivity that is embedded in and afforded by Web 2.0 applications and, second, the processes that are invisible to the composer. Successful compositional engagement with Web 2.0 applications requires an evolving interactive set of practices similar to those practiced by gamers, comics, and electronic literature authors and readers. What we learn about these practices has the potential to transform the way we understand writing and the teaching of writing within and outside of a Web 2.0 ecosystem.     

Online Conversation and Corporate Reputation: A Two‐Wave Longitudinal Study on the Effects of Exposure to the Social Media Activities of a Highly Interactive Company

In this paper, we investigate whether and to what extent exposure to a company's social media activities over time is beneficial for corporate reputation, and whether conversational human voice mediates this relation. In a two‐wave longitudinal survey among 1969 respondents, we assessed consumers' exposure to an international airline's social media activities, perceived level of conversational human voice and perception of corporate reputation. The results show that consumers' level of exposure to company social media activities precedes perceptions of corporate reputation. Also, conversational human voice mediates the relation between consumers' level of exposure to company social media activities and perceptions of corporate reputation. We discuss the implications of the results for the presence of organizations in social media.     

RETIN: A Content-Based Image Indexing and Retrieval System

This paper presents RETIN, a new system for automatic image indexing and interactive content-based image retrieval. The most original aspect of our work rests on the distance computation and its adjustment by relevance feedback. First, during an offline stage, the indexes are computed from attribute vectors associated with image pixels. The feature spaces are partitioned through an unsupervised classification, and then, thanks to these partitions, statistical distributions are processed for each image. During the online use of the system, the user makes an iconic request, i.e. he brings an example of the type of image he is looking for. The query may be global or partial, since the user can reduce his request to a region of interest. The comparison between the query distribution and that of every image in the collection is carried out by using a weighted dissimilarity function which manages the use of several attributes. The results of the search are then refined by means of relevance feedback, which tunes the weights of the dissimilarity measure via user interaction. Experiments are then performed on large databases and statistical quality assessment shows the good properties of RETIN for digital image retrieval. The evaluation also shows that relevance feedback brings flexibility and robustness to the search.     

Exploring activity theory as a tool for evaluating interactivity and learning in virtual environments for children

This paper explores the use of Activity Theory for the evaluation of user behaviour in immersive virtual environments. Specifically, the study of user behaviour focuses on interactivity, which is argued to be one of the most important processes that take place between a user and the system in virtual reality. The ultimate intention is to study the role and the effect of interactivity on learning and conceptual change and to examine how interaction and conceptual learning are related in the context of virtual environments developed primarily for informal educational settings. As a first step to this study, a set of exploratory experiments was carried out with children aged 7–12. The children were asked to complete tasks, such as the assembly of ancient columns from parts, which were designed to promote constructivist learning and explore the methods of carrying out in-depth experiments with children. This paper describes the analysis of these exploratory case studies from an Activity Theory perspective.

MDM光波导激发高阶SPP模的传输特性

研究了金属-介质-金属(MDM)型表面等离子体激元(SPP)光波导的电磁特性。理论计算结果表明,对于633nm的TM偏振入射光,当介质膜层厚度小于85nm时,波导中只能激发产生一阶SPP模(基模),其余高阶模全部截止。随着介质膜厚度增加,高阶SPP模逐渐被激发产生。当介质膜层厚度较小时,SPP模的有效折射率的实部随阶数的增加而减小,而虚部则随阶数的增加而增加,SPP基模具有最大传输距离。然而,当MDM波导中的介质层厚度超过0.555μm时,由于三阶SPP模的电磁场主要集中在离金属层相对较远的介质层中,其有效折射率的虚部具有最小值,具有最大的传输距离,而非基模。当入射光波长为633nm介质层厚度为0.9μm时,Ag/SiO2/Ag光波导中三阶SPP模的传输距离达到约150μm。