19812651
A Lattice of Abstract Graphs
This paper concerns the abstract interpretation of Term Graph Rewriting systems. We introduce a new lattice of abstract graphs; this improves over previous work in that the ordering is defined directly on the graph structure rather than via unravelling into trees. We use the lattice in sketching the correctness of Nocker's abstract reduction algorithm; an efficient strictness analysis used in the Concurrent Clean system.
14082519
Structuring and Design of Reactive Systems Using RSDS and B
With the advent of comprehensive safety standards for software intensive safety related systems, such as IEC 61508 and its speciali-sations for particular industry sectors (medical, machinery, process, etc), there is a need to establish combinations of techniques which can be used by industry to demonstrate conformance to these standards for particular developments. In this paper we describe one such combination of techniques, involving statecharts and B, which is aimed at reactive control system development. 
 
We define strategies for controller decomposition which allow safety invariants to be distributed into subcontroller requirements, and define techniques for the automatic synthesis of controllers from invariants. A case study of a train control system is used to illustrate the ideas.
21985459
Safety and Security Analysis of Object-Oriented Models
In this paper we review existing approaches for the safety and security analysis of object-oriented software designs, and identify ways in which these approaches can be improved and made more rigorous.
16641025
Quantified Interference for a While Language
We show how information theory can be used to give a quantitative definition of interference between variables in imperative programming languages. In this paper we focus on a particular case of this definition of interference: leakage of information from private variables to public ones in While language programs. The major result of the paper is a quantitative analysis for this language that employs a use-definition graph to calculate bounds on the leakage into each variable.
11325567
Design choices in the SHRIMP system: an empirical study
The SHRIMP cluster-computing system has progressed to a point of relative maturity; a variety of applications are running on a 16-node system. We have enough experience to understand what we did right and wrong in designing and building the system. In this paper we discuss some of the lessons we learned about computer architecture, and about the challenges involved in building a significant working system in an academic research environment. We evaluate significant design choices by modifying the network interface firmware and the system software in order to empirically compare our design to other approaches.
6229316
Thread scheduling for out-of-core applications with memory server on multicomputers
Out-of-core applications perform poorly in paged virtual memory (VM) systems because demand paging involves slow disk I/O accesses. Much research has been done on reducing the I/O overhead in such applications by either reducing the number of I/Os or lowering the cost of each I/O operation. In this paper, we investigate a method that combines finegrained threading with a memory server model to improve the performance of out-of-core applications on multicomputers. The memory server model decreases the average cost of I/O operations by paging to remote memory, while the fine-grained thread scheduling reduces the number of I/O accesses by improving the data locality of applications. We have evaluated this method on an Intel Paragon with 7 applications. Our results show that the memory server system performs better than the VM disk paging by a factor of 5 for sequential applications and a factor of 1.5 to 2.2 for parallel applications. The fine-grained threading alone improves the VM disk paging performance by a factor of 10 and 1.2 to 3 respectively for sequential and parallel applications. Overall, the combination of these two techniques outperforms the VM disk paging by more than a factor of 12 for sequential applications and a factor of 3 to 6 for parallel applications.
9494191
Visualization of height field data with physical models and texture photomapping
The paper discusses a unique way to visualize height field data-the use of solid fabricated parts with a photomapped texture to display scalar information. In this process, the data in a height field are turned into a 3D solid representation through solid freeform fabrication techniques, in this case laminated object manufacturing. Next, that object is used as a 3D "photographic plate" to allow a texture image representing scalar data to be permanently mapped onto it. The paper discusses this process and how it can be used in different visualization situations.
53240736
Early Experience with Message-Passing on the SHRIMP Multicomputer
6156615
The design philosophy of the DARPA internet protocols
The Internet protocol suite, TCP/IP, was first proposed fifteen years ago. It was developed by the Defense Advanced Research Projects Agency (DARPA), and has been used widely in military and commercial systems. While there have been papers and specifications that describe how the protocols work, it is sometimes difficult to deduce from these why the protocol is as it is. For example, the Internet protocol is based on a connectionless or datagram mode of service. The motivation for this has been greatly misunderstood. This paper attempts to capture some of the early reasoning which shaped the Internet protocols.