This paper summarizes our work adapting a recursive digital resonator for use on sixteen-bit fixed-point hardware. Our modified oscillator is a two-pole filter that maintains frequency precision at a cost of two additional operations per filter sample. The new filter's error properties are expressly matched to use in the range of frequencies relevant to additive synthesis of digital audio and sinusoidal modelling of speech in order to minimize the additional computational overhead. We present the algorithm, an error analysis, a performance analysis, and measurements of an implementation on a fixed-point vector microprocessor system.

The widespread deployment of inexpensive communications technology, computational resources in the networking infrastructure, and network-enabled end devices poses an interesting problem for end users: how to locate a particular network service or device out of hundreds of thousands of accessible services and devices.This paper presents the architecture and implementation of a secure Service Discovery Service (SDS).Service providers use the SDS to advertise complex descriptions of available or already running services, while clients use the SDS to compose complex queries for locating these services.Service descriptions and queries use the extensible Markup Language (XML) to encode such factors as cost, performance, location, and device-or service-specific capabilities.The SDS provides a highlyavailable, fault-tolerant, incrementally scalable service for locating services in the wide-area.Security is a core component of the SDS and, where necessary, communications are both encrypted and authenticated.Furthermore, the SDS uses an hybrid access control list and capability system to control access to service information.

This paper introduces the notion of “universal interaction,” allowing a device to adapt its functionality to exploit services it discovers as it moves into a new environment. Users wish to invoke services — such as controlling the lights, printing locally, or reconfiguring the location of DNS servers — from their mobile devices. But aprioristandardization of interfaces and methods for service invocation is infeasible. Thus,the challenge is to develop a new service architecture that supports heterogeneity in client devices and controlled objects, and which makes minimal assumptions about standard interfaces and control protocols. There are five components to a comprehensive solution to this problem: 1) allowing device mobility, 2) augmenting controllable objects to make them network-accessible, 3) building an underlying discovery architecture, 4) mapping between exported object interfaces and client device controls, and 5) building complex behaviors from underlying composable objects. We motivate the need for these components by using an example scenario to derive the design requirements for our mobile services architecture. We then present a prototype implementation of elements of the architecture and some example services using it, including controls to audio/visual equipment, extensible mapping, server autoconfiguration, location tracking, and local printer access.

We analyze the impact of wiresizing on the performance of Elmore-based routing constructions. Whereas previous wiresizing schemes are static (i.e., they wiresize an existing topology), we introduce a new dynamic wiresizing technique, which uses wiresizing considerations to drive the routing construction itself. Simulations show that dynamic wiresizing affords superior performance over static wiresizing, and also avoids topological degeneracies. Moreover, dynamically-wiresized Elmore-based routing constructions significantly outperform all previous methods (including A-Trees) in term of maximum source-sink signal delay, affording to 73% average SPICE delay improvement over traditional Steiner routing.>