This paper highlights the requirements engineering approach tailored to the unique complexities of developing system requirements for the retrofit of subsea equipment used in offshore deepwater operations. A feasible system in this application must satisfy demanding stakeholder needs in safety, reliability, availability, maintainability, retrofittability, deployment timelines, interface compatibility and regulatory conformance. Additionally, the system requirements must be defendable against the industry's decades-long established regulatory, cultural and technological legacies. To objectively define the system requirements within these constraints, the conventional INCOSE requirements engineering process including analysis, allocation, refinement, and traceability was tailored specifically to the project leveraging aspects of Model Based Systems Engineering (MBSE). A novel approach for tracing specific clauses contained within industry standards and regulations to system requirements is discussed, including a methodology for capturing conformance, equivalence and alternative means of compliance. The tailored requirements engineering process utilizing commercially available systems engineering software tools is presented.

Abstract Implementing a concurrent programming language such as Java by means of a translator to an existing language is attractive as it provides portability over all platforms supported by the host language and reduces development time—as many low‐level tasks can be delegated to the host compiler. The C and C++ programming languages are popular choices for many language implementations due to the availability of efficient compilers on a wide range of platforms. For garbage‐collected languages, however, they are not a perfect match as no support is provided for accurately discovering pointers to heap‐allocated data on thread stacks. We evaluate several previously published techniques and propose a new mechanism, lazy pointer stacks, for performing accurate garbage collection in such uncooperative environments. We implemented the new technique in the Ovm Java virtual machine with our own Java‐to‐C/C++ compiler using GCC as a back‐end compiler. Our extensive experimental results confirm that lazy pointer stacks outperform existing approaches: we provide a speedup of 4.5% over Henderson's accurate collector with a 17% increase in code size. Accurate collection is essential in the context of real‐time systems, we thus validate our approach with the implementation of a real‐time concurrent garbage collection algorithm. Copyright © 2009 John Wiley & Sons, Ltd.

This paper reports on our experience with the implementation of the Real-time Specification for Java on the Ovm open source Java virtual machine. We describe the architecture and main design decisions involved in implementing real-time Java on Ovm. We present the first use of Real-time Java in avionics in the context of control software for a ScanEagle Unmanned Aerial Vehicle.

We present a new concurrency control abstraction for real-time systems called preemptible atomic regions (PARs). PARs a transactional mechanism that improves upon lock-based mutual exclusion in several ways. First, and foremost, PARs provide strong correctness guarantees. Any sequence of operations declared atomic will not suffer interference from other threads, even in the presence of programmer errors. In spite of this, PARs can be preempted by high priority tasks; this is essential to the minimization of blocking times. We have implemented PARs in a uniprocessor real-time Java virtual machine and evaluated their utility on a number of programs. The results suggest that programs that use PARs, depending on their semantics, can run faster and experience less jitter than those that use locks

This paper presents an improved technique for determining the 3D structure of the human face form stereo images. The approach targets specific regions of the face individually. An application of the approach to estimate the 3D structure of the nose is presented. Stereo matching is extended and applied to colour in addition to grayscale, which improves matching in a low texture image like parts of the skin of a human face. Left-right consistency check is used to determine erroneous disparity estimates. Prior knowledge of the nose structure is used in conjunction to improve the quality of the 3D nose estimates.

We have designed and implemented Maya, a version of Java that allows programmers to extend and reinterpret its syntax. Maya generalizes macro systems by treating grammar productions as generic functions, and semantic actions on productions as multimethods on the corresponding generic functions. Programmers can write new generic functions (i.e., grammar productions) and new multimethods (i.e., semantic actions), through which they can extend the grammar of the language and change the semantics of its syntactic constructs, respectively. Maya's multimethods are compile-time metaprograms that transform abstract syntax: they execute at program compile-time, because they are semantic actions executed by the parser. Maya's multimethods can be dispatched on the syntactic structure of the input, as well as the static, source-level types of expressions in the input. In this paper we describe what Maya can do and how it works. We describe how its novel parsing techniques work and how Maya can statically detect certain kinds of errors, such as code that generates references to free variables. Finally, to demonstrate Maya's expressiveness, we describe how Maya can be used to implement the MultiJava language, which was described by Clifton et al. at OOPSLA 2000.