Robin B. Stanton

Type-Safe Linguistic Reflection: A Generator Technology

Reflective systems allow their own structures to be altered from within. In a programming system reflection can occur in two ways: by a program altering its own interpretation or by it changing itself. Reflection has been used to facilitate the production and evolution of data and programs in database and programming language systems. This paper is concerned with a particular style of reflection, called linguistic reflection, used in compiled, strongly typed languages. Two major techniques for this have evolved: compile-time reflection and run-time reflection. These techniques are described together with a definition and anatomy of reflective systems using them. Two illustrative examples are given and the uses of type-safe reflective techniques in a database programming language context are surveyed. These include attaining high levels of genericity, accommodating changes in systems, implementing data models, optimising implementations and validating specifications.

Supporting Coarse and Fine Grain Parallelism in an Extension of ML

We have built an extension of Standard ML aimed at multicomputer platforms with distributed memories. The resulting language, paraML, differs from other extensions by including and differentiating both coarse-grained and fine-grained parallelism.

Recovery and page coherency for a scalable multicomputer object store

The paper presents scalable algorithms for recovery and page coherency in multicomputer object stores. Recovery and coherency are central to object store engineering and distributed memory multicomputers are fundamental to scalable computation. Efficient recovery is implemented through a combination of local logging and a localisation of the transactional workspace model. A vector of update counts is used to efficiently represent global time. The algorithms have been successfully implemented and tested on a 128 node Fujitsu AP1000 distributed memory multicomputer. The paper presents performance results which indicate good performance and scalability for these algorithms under a range of situations. The work is seen as a step in the continuing development of high performance multicomputer object stores.

A planner for time-space coordination of robots in a structured workspace

In industrial applications, tasks for robotic workcells are typically specified by programs written in conventional programming languages such as VAL-II and Karel. Devising planners which synthesize programs from high-level specification statements is a research problem of considerable difficulty, owing to the multiagent, real-time nature of the activities of a robotic workcell. An experimental planner for such high-level task specification is described. The planner is based on abstracting the time-space coordination aspects typical of a wide range of manufacturing tasks. The planner architecture consists of three modules, with the functions of plan generation (providing partially elaborated plans), space-time planning (yielding fully elaborated plans), and the monitoring of plan execution.<<ETX>>