120 research outputs found
A Formal Verification Environment for Use in the Certification of Safety-Related C Programs
In this thesis the design of an environment for the formal verification of functional properties of safety-related software written in the programming language C is described. The focus lies on the verification of (primarily) geometric computations. We give an overview of the applicable regulations for safety-related software systems. We define a combination of higher-order logic as formalised in the theorem prover Isabelle and a specification language syntactically based on C expressions. The language retains the mathematical character of higher-level specifications in code specifications. A memory model for C is formalised which is appropriate to model low-level memory operations while keeping the entailed verification overhead in tolerable bounds. Finally, a Hoare style proof calculus is devised so that correctness proofs can be performed in one integrated framework. The applicability of the approach is demonstrated by describing its use in an industrial project
First Annual Workshop on Space Operations Automation and Robotics (SOAR 87)
Several topics relative to automation and robotics technology are discussed. Automation of checkout, ground support, and logistics; automated software development; man-machine interfaces; neural networks; systems engineering and distributed/parallel processing architectures; and artificial intelligence/expert systems are among the topics covered
Quantitative prediction of quality attributes for component-based software architectures
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The occurrence and origin of salinity in non-coastal groundwater in the Waikato region
Aims
The aims of this project are to describe the occurrence, and determine the origin of non-coastal saline groundwater in the Waikato region. High salinity limits the use of the water for supply and agricultural use.
Understanding the origin and distribution of non-coastal salinity will assist with development and management of groundwater resources in the Waikato.
Method
The occurrence of non-coastal groundwater salinity was investigated by examining driller’s records and regional council groundwater quality information. Selected wells were sampled for water quality analyses and temperatures were profiled where possible. Water quality analyses include halogens such as chloride, fluoride, iodide and bromide. Ratios of these ions are useful to differentiate between geothermal and seawater origins of salinity (Hem, 1992). Other ionic ratio approaches for differentiating sources and influences on salinity such as those developed by Alcala and Emilio (2008) and Sanchez-Martos et al.,
(2002), may also be applied. Potential sources of salinity include seawater, connate water, geothermal and anthropogenic influences. The hydrogeologic settings of saline occurrence were also investigated, to explore the potential to predict further occurrence.
Results
Numerous occurrences of non-coastal saline groundwater have been observed in the Waikato region.
Where possible, wells with relatively high total dissolved solids (TDS) were selected for further investigation.
Several groundwater samples are moderately saline and exceed the TDS drinking water aesthetic guideline
of 1,000 g m-3 (Ministry of Health, 2008).
Selected ion ratios (predominantly halogens) were used to assist in differentiating between influences on salinity such as seawater and geothermal. Bromide to iodide ratios, in particular, infer a greater geothermal influence on salinity, although other ratios are not definitive.
The anomalously elevated salinity observed appears natural but nevertheless has constrained localised groundwater resource development for dairy factory, industrial and prison water supply use. Further work may show some relationship with geology or tectonics, which could assist prediction of inland saline groundwater occurrence
Modelling and simulation of paradigms for printed circuit board assembly to support the UK's competency in high reliability electronics
The fundamental requirement of the research reported within this thesis is the provision
of physical models to enable model based simulation of mainstream printed circuit
assembly (PCA) process discrete events for use within to-be-developed (or under
development) software tools which codify cause & effects knowledge for use in product
and process design optimisation. To support a national competitive advantage in high
reliability electronics UK based producers of aircraft electronic subsystems require
advanced simulation tools which offer model based guidance. In turn, maximization of
manufacturability and minimization of uncontrolled rework must therefore enhance inservice
sustainability for ‘power-by-the-hour’ commercial aircraft operation business
models. [Continues.
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