This paper describes our design of a simulation environment for electronic textiles (e-textiles) and our experiences with that environment. This simulation environment, based upon Ptolemy II, enables us to model a diverse range of areas related to the design of electronic textiles, including the physical environment they will be used in, the behavior of the sensors incorporated into the fabric, the on-fabric network, the power consumption of the system, and the execution of the application and system software. This paper focuses on two aspects of the system, modeling the motion of a person wearing the e-textile and modeling the effect of faults in the e-textile system. To partially validate this environment, we compare simulation results against results from two different physical prototypes, a large-scale acoustic beamformer and a pair of shape-sensing pants.

We describe the implementation of a type checker for the functional programming language Haskell that supports the use of type classes . This extends the type system of ML to support overloading (ad-hoc polymorphism) and can be used to implement features such as equality types and numeric overloading in a simple and general way. The theory of type classes is well understood, but the practical issues involved in the implementation of such systems have not received a great deal of attention. In addition to the basic type checking algorithm, an implmenentation of type classes also requires some form of program transformation. In all current Haskell compilers this takes the form of dictionary conversion, using functions as hidden parameters to overloaded values. We present efficient techniques for type checking and dictionary conversion. A number of optimizations and extensions to the basic type class sytems are also described.

Touch-screen systems have been used to count votes in a growing number of precincts across the United States. These controversial systems provide an opportunity for valuable classroom discussions both for service courses and courses for computer science majors This paper begins with an overview of touch-screen voting systems in the United States. It describes ways to productively address this issue with university classes at various levels in the curriculum. It is hoped that this paper will be a useful resource to professors looking to bring this important issue into their classroom, perhaps as a partial requirement of an ethics and social implications module of a course's coverage.

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