A copying collector has two excellent properties: it compacts the heap, and the execution time depends solely on the number of live objects. Use of a copying collector is thought by some to be a more efficient way of managing the heap than explicit freeing of objects. This paper describes a high-performance copying collector for a hybrid object-oriented language. The collector is both conservat...

Complex soflware environments, such as CAD systems, consist of many modules which are often created, maintained, and executed separately. When slick systems are invoked, appropriate execution sequences and parameters must be determined for each modiile so that desired results are produced. The task of planning, executing, and supervising the CAD environments has become so complex that it itself...

For millennia, seeds have been freely available to use for farming and plant breeding without restriction. Within the past century, however, intellectual property rights (IPRs) have threatened this tradition. In response, a movement has emerged to counter the trend toward increasing consolidation of control and ownership of plant germplasm. One effort, the Open Source Seed Initiative (OSSI, www...

This paper presents a fast numerical solution for the inverse kinematics of a serial manipulator. The method is implemented on the C-Arm, a manipulator designed for use in robotic surgery. The inverse kinematics solution provides all possible solutions for any six degree-of-freedom serial manipulator, assuming the forward kinematics are known and that it is possible to solve for the remaining j...

Starting with fewer degrees of freedom has been shown to enable a more efficient exploration of the sensorimotor space. While not necessarily leading to optimal task performance, it results in a smaller number of directions of stability, which guide the coordination of additional degrees of freedom. The developmental release of additional degrees of freedom is then expected to allow for optimal...

A major issue slowing the development of cluster computers is that programs that efficiently take advantage of them are difficult to write. Cluster programming adds a whole facet to sequential programming; requiring specification of not just when an operation will run, but also where it will be ran. Communications packages such as MPI and PVM explicitly express communications between the nodes ...