Institute of Information Science, Academia Sinica

The Domain Name System (DNS) is a foundation stone of the Internet. It helps Internet applications find hosts’ IP addresses. However, it does not support multilingual domain names. In past years, several multilingual domain name service trials had started. However, some incompatibilities of these solutions had introduced unexpected behaviors of users’ applications. We studied these problems, while participated in the IETF (Internet Engineering Task Force) standardization of Internationalized Domain Name (IDN) – IDNA. In this article, we proposed a server proxy architecture for IDN resolution without modification to existent Internet software. A Chinese domain name service trial had started in Institute of Information Science, Academia Sinica in 2002. We further investigated several types of errors when IDNs are used in various Internet softwares. Best common practices at this stage are presented. These experiences give rich guidance for software providers to develop IDNA-compliant Internet applications.

The success of Skype has inspired a generation of peer-to-peer-based solutions for satisfactory real-time multimedia services over the Internet. However, fundamental questions, such as whether VoIP services like Skype are good enough in terms of user satisfaction, have not been formally addressed. One of the major challenges lies in the lack of an easily accessible and objective index to quantify the degree of user satisfaction.
In this work, we propose a model, geared to Skype, but generalizable to other VoIP services, to quantify VoIP user satisfaction based on a rigorous analysis of the call duration from actual Skype traces. The User Satisfaction Index (USI) derived from the model is unique in that 1) it is composed by objective source- and network-level metrics, such as the bit rate, bit rate jitter, and round-trip time, 2) unlike speech quality measures based on voice signals, such as the PESQ model standardized by ITU-T, the metrics are easily accessible and computable for real-time adaptation, and 3) the model development only requires network measurements, i.e., no user surveys or voice signals are necessary. Our model is validated by an independent set of metrics that quantifies the degree of user interaction from the actual traces.

Generally, decomposition is a leverage to obtain the componential representation from a whole. After the decomposition step is executed, the decomposed components can be individually selected, grouped, and analyzed based on the properties of interest. According to Hoffman and Singh’s theory [1], there are at least three factors that determine the salience of a part: the protrusion, the boundary strength, and the relative size. However, the quantitative definitions for part salience proposed by Hoffman and Singh [1] were made under the assumption that a part and its boundary are found in advance. In this paper, we propose a new 3D mesh decomposition scheme that incorporates the psychological theory of visual salience, in such a way that the mesh decomposition process is as close as possible to the human visual perception mechanism.

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