The BEA aqualogic data services platform (ALDSP) is a middleware platform for creating services that integrate and manipulate information from disparate enterprise data sources. This paper provides a technical overview of the all-new update support in ALDSP 3.0, released in January 2008. It describes the update side of data services, our unique model for making update automation transparent and flexible, and the use of the XQuery Scripting Extension (XQSE) for further customizing the system's default handling of updates. It also gives an overview of the ALDSP update processing machinery, including the automatic generation of update maps from read functions, translation of update maps into update virtual machine (UVM) programs, the UVM instruction interpreter, and SQL generation for updates to data drawn from relational data sources.

The AquaLogic Data Services Platform (ALDSP) is a middleware platform for building data services that integrate and provide operations over data drawn from spanning multiple heterogeneous information sources. A data service consists of an XML Schema instance, describing its information content, and a collection of XQuery functions and procedures that comprise its set of operations. This paper describes access control in ALDSP. We describe ALDSP's securable resource hierarchy, its fine-grained access control capabilities for securing portions of data service schemas, how XQuery can be used to specify data-driven security policies, and how user identity mapping is supported. We then provide an in-depth overview of how ALDSP works, including implementation techniques to keep access control checking from interacting badly with view rewriting, query optimization, and caching.

Immersive audio systems can be used to render virtual sound sources in three-dimensional (3-D) space around a listener. This is achieved by simulating the head-related transfer function (HRTF) amplitude and phase characteristics using digital filters. In this paper, we examine certain key signal processing considerations in spatial sound rendering over headphones and loudspeakers. We address the problem of crosstalk inherent in loudspeaker rendering and examine two methods for implementing crosstalk cancellation and loudspeaker frequency response inversion in real time. We demonstrate that it is possible to achieve crosstalk cancellation of 30 dB using both methods, but one of the two (the Fast RLS Transversal Filter Method) offers a significant advantage in terms of computational efficiency. Our analysis is easily extendable to nonsymmetric listening positions and moving listeners.

Immersive audio systems are being envisioned for applications that include teleconferencing and telepresence; augmented and virtual reality for manufacturing and entertainment; air traffic control, pilot warning, and guidance systems; displays for the visually-impaired; distance learning; and professional sound and picture editing for television and film. The principal function of such systems is to synthesize, manipulate and render sound fields in real time. In this paper we examine several signal processing considerations in spatial sound rendering over loudspeakers. We propose two methods that can be used to implement the necessary filters for generating virtual sound sources based on synthetic head-related transfer functions with the same spectral characteristics as those of the real source.