53774387
Handwriting authentication by envelopes of sound signature
Frictions between a rigid-nib pen and paper result in audible sounds that are correlated with the dynamics of writing. Such writing-sounds were previously used as a biometric identity to achieve writer authentication. This paper presents an alternative and supplement algorithm for sound-based handwriting authentication. Envelopes of writing-sounds estimated by the Hilbert transforms are found useful in differentiating topologically similar characters written by different individuals. A straightforward supervised neural network in conjunction with a purpose-designed pre-processor can be trained on examples to effectively differentiate patterns of writing-sounds and thus achieve writer authentication, providing a straightforward and potential alternative to existing methods.
35522380
A neural network model for speech intelligibility quantification
A neural network based model is developed to quantify speech intelligibility by blind-estimating speech transmission index, an objective rating index for speech intelligibility of transmission channels, from transmitted speech signals without resort to knowledge of original speech signals. It consists of a Hilbert transform processor for speech envelope detection, a Welch average periodogram algorithm for envelope spectrum estimation, a principal components analysis (PCA) network for speech feature extraction and a multi-layer back-propagation network for non-linear mapping and case generalisation. The developed model circumvents the use of artificial test signals by exploiting naturally occurring speech signals as probe stimuli, reduces measurement channels from two to one and hence facilitates in situ assessment of speech intelligibility. From a cognitive science viewpoint, the proposed method might be viewed as a successful paradigm of mimicking human perception of speech intelligibility using a hybrid model built around artificial neural networks.
45616322
Increasing FPGA resilience against soft errors using task duplication
17558341
Adaptive partitioning for multi-server distributed virtual environments
A distributed virtual environment (DVE) allows users at different geographical locations to share information and interact within a common virtual environment (VE) via a local network or through the Internet. However, when the number of users exploring the VE increases, the server will quickly become the bottleneck. To enable good performance, we are currently developing a multi-server DVE prototype. In this paper, we describe an adaptive data partitioning technique to dynamically partition the whole VE into regions. All objects within each region will be managed by a single server. As the loading of the servers changes, we show how it can be redistributed while minimizing the communication cost. Our initial results show that the proposed adaptive partitioning technique significantly improves the performance of the overall system.
9337355
Weather forecasting: predicting performance for streaming video over wireless LANs
The growth of wireless LANs has brought the expectation for high-bitrate streaming video to wireless PCs. However, it remains unclear how wireless channel characteristics impact the quality of streaming video sent over wireless LANs. This paper presents results from experiments that stream commercial video over a wireless campus network. By analyzing the streaming video quality and capturing wireless LAN characteristics across network and wireless link layers, "weather forecasts" are created such that selected wireless LAN performance indicators might be used to predict the streaming video quality. Furthermore, a quantified measurement of accuracy is presented to evaluate the effectiveness of individual weather forecasts. The paper evaluates six distinct weather forecasts four different streaming configurations including TCP and UDP streaming, and single and multiple-level encoded videos. The results show that the wireless Received Signal Strength Indicator (RSSI) and average wireless link capacity are the most accurate indicators to predict the performance of streaming video over wireless LANs. The weather forecast philosophy can be beneficial for adapting video streaming in wireless LAN environments.
1528533
Application, Network and Link Layer Measurements of Streaming Video over a Wireless Campus Network
The growth of wireless LANs has brought the expectation for high-bitrate streaming video to wireless PCs. However, it remains unknown how to best adapt video to wireless channel characteristics as they degrade. This paper presents results from experiments that stream commercial video over a wireless campus network and analyze performance across application, network and wireless link layers. Some of the key findings include: 1) Wireless LANs make it difficult for streaming video to gracefully degrade as network performance decreases; 2) Video streams with multiple encoding levels can more readily adapt to degraded wireless network conditions than can clips with a single encoding level; 3) Under degraded wireless network conditions, TCP streaming can provide higher video frame rates than can UDP streaming, but TCP streaming will often result in significantly longer playout durations than will UDP streaming; 4) Current techniques used by streaming media systems to determine effective capacity over wireless LAN are inadequate, resulting in streaming target bitrates significantly higher than can be effectively supported by the wireless network.
2909871
ConNexus to awarenex: extending awareness to mobile users
We explored the use of awareness information to facilitate communication by developing a series of prototypes. The ConNexus prototype integrates awareness information, instant messaging, and other communication channels in an interface that runs on a desktop computer. The Awarenex prototype extends that functionality to wireless handheld devices, such as a Palm. A speech interface also enables callers to make use of the awareness information over the telephone. While the prototypes offer similar functionality, the interfaces reflect the different design affordances and use context of each platform. We discuss the design implications of providing awareness information on devices with varying interface and network characteristics.