Brief Announcement: On the Impossibility of Detecting Concurrency

We identify a general principle of distributed computing: one cannot force two processes running in parallel to see each other. This principle is formally stated in the context of asynchronous processes communicating through shared objects, using trace-based semantics. We prove that it holds in a reasonable computational model, and then study the class of concurrent specifications which satisfy this property. This allows us to derive a Galois connection theorem for different variants of linearizability

Communicating Java Threads

The incorporation of multithreading in Java may be considered a significant part of the Java language, because it provides udimentary facilities for concurrent programming. However, we belief that the use of channels is a fundamental concept for concurrent programming. The channel approach as described in this paper is a realization of a systematic design method for concurrent programming in Java based on the CSP paradigm. CSP requires the availability of a Channel class and the addition of composition constructs for sequential, parallel and alternative processes. The Channel class and the constructs have been implemented in Java in compliance with the definitions in CSP. As a result, implementing communication between processes is facilitated, enabling the programmer to avoid deadlock more easily, and freeing the programmer from synchronization and scheduling constructs. The use of the Channel class and the additional constructs is illustrated in a simple application

Life of occam-Pi

This paper considers some questions prompted by a brief review of the history of computing. Why is programming so hard? Why is concurrency considered an “advanced” subject? What’s the matter with Objects? Where did all the Maths go? In searching for answers, the paper looks at some concerns over fundamental ideas within object orientation (as represented by modern programming languages), before focussing on the concurrency model of communicating processes and its particular expression in the occam family of languages. In that focus, it looks at the history of occam, its underlying philosophy (Ockham’s Razor), its semantic foundation on Hoare’s CSP, its principles of process oriented design and its development over almost three decades into occam-? (which blends in the concurrency dynamics of Milner’s ?-calculus). Also presented will be an urgent need for rationalisation – occam-? is an experiment that has demonstrated significant results, but now needs time to be spent on careful review and implementing the conclusions of that review. Finally, the future is considered. In particular, is there a future

The Role of Sculpture in Communicating Archaeology in Museums

In this article I discuss an innovative museum strategy that aims to create a more evocative and engaging visitor experience. I argue that the inclusion of contemporary art, and specifically sculpture in exhibition design, activates visitor agency, empowering the public to take part in interpreting the human past. I explore the unique sensory engagement sculpture provides and the important role this can play for the public presentation of archaeology. I also examine an existing project that has called upon sculpture as an interpretive resource at the National Museum of Scotland, discussing its impact on visitors and its contribution to the discipline. I conclude with a discussion of a selection of living sculptors including Rachel Whiteread and Antony Gormley whose work, I argue, signals exciting opportunities for future artist-curator collaboration. By considering both current examples and future possibilities, this article builds a case for sculpture as an important and dynamic tool for the public understanding of archaeology in museums

From Functions to Object-Orientation by Abstraction

In previous work we developed a framework of computational models for function and object execution. The models on an higher level of abstraction in this framework allow for concurrent execution of functions and objects. We show that the computational model for object execution complies with the fundamentals of object-orientation.Comment: arXiv admin note: text overlap with arXiv:1010.3100, arXiv:1111.5172, arXiv:1208.334

DHARMAKIRTI, DAVIDSON, AND KNOWING REALITY

If we distinguish phenomenal effects from their noumenal causes, the former being our conceptual(ized) experiences, the latter their grounds or causes in reality as it is independent of our experience, then two contradictory positions with regards to the relationship between these two can be distinguished: either phenomena are identical with their noumenal causes, or they are not. Davidson is among the most influential modern defenders of the former position, metaphysical non-dualism. Dharmakirti\u27 strict distinction between ultimate and conventional reality, on the other hand, may be one of the most rigorously elaborated theories of the opposite position, metaphysical dualism. Despite this fundamental difference, their theories about the connection between phenomena and their noumenal causes are surprisingly similar in important respects. Both Dharmakirti in his theory of apoha and Davidson in his theory of triangulation argued that the content of words or concepts depends on a process involving at least two communicating beings and shared noumenal stimuli. The main point of divergence is the nature of classification, but ultimately Dharmakirti\u27s and Davidson\u27s conclusions on the noumenal-phenomenal relationship turn out to be complementary more than contradictory, and an integrative reconstruction suggests a middle path between dualism and non-dualism

Ambiguity is a double-edged sword: similarity references in communication

Designers often explain new concepts and new ideas by reference to existing designs. This is parsimonious, as it only requires a pointer to the referent and a description of the modifications. Such descriptions can be extremely powerful, expressing the entire context of a design or a process in a few words. However similarity assertions are inherently ambiguous, because they depend not only on the chosen description but also on the intention behind the similarity comparison. In this paper we attempt to analyse the effect that the ambiguity of similarity references has on communication and idea generation in design. The reinterpretation of a similarity assertion can be extremely creative, where ambiguity allows for new interpretations of a problem. At the same time, it can make accurate communication extremely difficult because every assertion can be interpreted differently unless the context is fully shared

Memory transition between communicating agents

Abstract: What happens to a memory when it has been externalised and embodied but has not reached its addressee yet? A letter that has been written but has not been read, a monument before it is unveiled or a Neolithic tool buried in the ground – all these objects harbour human memories engrained in their physicality; messages intended for those who will read the letter, admire the monument and hold the tool. According to Ilyenkov’s theory of objective idealism, the conscious and wilful input encoded in all manmade objects as the ‘ideal’ has an objective existence, independent from the author, but this existence lasts only while memories are shared between communicating parties. If all human minds were absent from the world for a period of time, the ‘ideal’, or memories, would cease to exist. They would spring back to existence, however, once humans re-entered the world. Ilyenkov’s analysis of memories existing outside an individual human consciousness is informative and thorough but, following his line of thought, we would have to accept an ontological gap in the process of memory acquisition, storage and transmission. If there is a period, following memory acquisition and receding its transmission, when memories plainly do not exist, then each time a new reader, spectator or user perceives them, he or she must create the author’s memories ex nihilo. Bergson’s theory of duration and intuition can help us to resolve this paradox. This paper will explore the ontological characteristics of memory passage in communication taken at different stages of the process. There will be an indicationof how the findings of this investigation could be applicable to concrete cases of memory transmission. In particular, this concerns intergenerational communication, technological memory, the use of digital devices and the Internet