Non-deterministic Form Research Articles

The Unfolding: Origins, Techniques, and Applications within Discrete Event Systems

This article aims to provide a perspective on the foundations and developments of the net unfolding techniques and their applications to discrete event systems. The numerous methods applied to concurrency presented in the literature can be roughly divided into two classes: those that assume concurrency can be represented by means of a non-deterministic form, and those that represent concurrency by means of causal relations. This study serves as an ideal starting point for researchers interested in true concurrency semantics by offering a concise literature review of one of the major streams of research towards concurrency and interleaving problems. In order to cope with the state-explosion problem, the unfolding approach is used. Based on the findings of concurrency theory, interleaving semantics are replaced with a unique partially ordered occurrence net. In this paper, we aim to provide a comprehensive review on the history of net unfoldings, the methods that are based on these unfoldings, and how they are used in discrete event systems for automatic verification and compact representations purposes.

Stochastic Modeling of a DFIG Wind Turbine in Matpower

One of the main trends in the electric power industry is the use of green energy – renewable energy sources (RES), especially wind power generation. The penetration of large wind turbine (WT) power capacity leads to changes in the topology and characteristics of electric power systems (EPS), which can cause an increase the likelihood of emergency processes and a decrease in the steady-state and transient EPS stability. The issue arises in ensuring the EPS stability with RES units, especially in the case of large disturbances. The main way to solve this issue is mathematical modeling. However, almost all the main currently used software programs are based on deterministic methods for calculating EPS processes, which are not able to consider all possible state uncertainties. To reliably determine all possible states of the system in which it can be, it is necessary to determine in a non-deterministic form how the values in the nodes and branches will be distributed. The peculiarity of this paper is associated with the use of a set of approaches to increase the accuracy of the results obtained: the approximation method in combination with two goodness-of-fit criteria for wind; the SIBD method, which generates the required probability density without loss of density values; and the controlled discretization of input variables. This paper assumes the formation of a WT stochastic model to study the impact of RES on stability in a non-deterministic form using the example of IEEE standard bus systems in the Matpower program.

Exploring different automata representations for efficient regular expression matching on GPUs

Regular expression matching is a central task in several networking (and search) applications and has been accelerated on a variety of parallel architectures. All solutions are based on finite automata (either in deterministic or non-deterministic form), and mostly focus on effective memory representations for such automata. Recently, a handful of work has proposed efficient regular expression matching designs for GPUs; however, most of them aim at achieving good performance on small datasets. Nowadays, practical solutions must support the increased size and complexity of real world datasets. In this work, we explore the deployment and optimization of different GPU designs of regular expression matching engines, focusing on large datasets containing a large number of complex patterns.

The Prosumer and the Project Studio: The Battle for Distinction in the Field of Music Recording

Using participant observation and content analysis of musicians’ internet newsgroups and bulletin boards, my research examines the creation of a new socio-historic subject (‘the prosumer’) and space of production (‘the project studio’). Prosumers’ practices illustrate a nondeterministic form of structural causation that both supports and refutes Bourdieu’s theory of cultural/social (re)production. In support of Bourdieu, my empirical research illustrates the relative autonomy of the habitus and shows that cultural production can foster social change. Although Bourdieu repeatedly made such theoretical claims, his struggle to empirically support them led critics to characterize his work as a synchronously reproductive form of economic reductionism. While I reject these critiques, my work does problematize Bourdieu’s understanding of ‘capital conversion’ and complicates his somewhat ‘straightforward’ relation of cultural practice to economic class. Such ‘relations and conversions’ presuppose clearly separated economic/cultural and productive/ consumptive social spheres. Since ‘prosumption’ blurs these demarcations, we must subsequently reassess aspects of Bourdieu’s work.

Sliding bifurcations and non-determinism in systems with switching

AbstractDynamical events associated with loss of determinacy in piecewise-smooth dynamical systems are reviewed. The causes of non-determinacy are discussed, and the conditions for their occurence in general systems are derived. These events can be characterized in terms of recently classified catastrophic sliding bifurcations and a non-deterministic form of chaos, which are shown to provide generic scenarios for non-determinacy to affect stable dynamical behaviour. The particular conditions for these are derived in a canonical (Lur'e) model of switched feedback control, and explicit examples are given in two and three dimensions.

Darwin's Doubt, Non-deterministic Darwinism and the Cognitive Science of Religion

AbstractAlvin Plantinga, echoing a worry of Charles Darwin which he calls ‘Darwin's doubt’, argues that given Darwinian evolutionary theory our beliefs are unreliable, since they are determined to be what they are by evolutionary pressures and could have had no other content. This papers surveys in turn deterministic and non-deterministic interpretations of Darwinism, and concludes that Plantinga's argument poses a problem for the former alone and not for the latter. Some parallel problems arise for the Cognitive Science of Religion, and in particular for the hypothesis that many of our beliefs, including religious beliefs, are due to a Hypersensitive Agency-Detection Device, at least if this hypothesis is held in a deterministic form. In a non-deterministic form, however, its operation need not cast doubt on the rationality or reliability of the relevant beliefs.

Symposium on Ellen Meiksins Wood's Empire of Capital: Editorial Introduction

AbstractEllen Wood's study of the new imperialism represents the latest instance of her broader project of reconstituting a non-deterministic form of Marxism which is able both to explain the historical specificity of capitalism and to inform socialist political activity. This essay seeks to locate her analysis of imperialism both in the wider political context within which it was written and as an example of the fecundity of her re-interpretation of historical materialism. After outlining the main themes of Wood's 'political-Marxist' project, I move on to overview the thesis of her book Empire of Capital (2003) before finally pointing to the main themes of the ensuing debate.

Fast and flexible string matching by combining bit-parallelism and suffix automata

The most important features of a string matching algorithm are its efficiency and its flexibility. Efficiency has traditionally received more attention, while flexibility in the search pattern is becoming a more and more important issue. Most classical string matching algorithms are aimed at quickly finding an exact pattern in a text, being Knuth-Morris-Pratt (KMP) and the Boyer-Moore (BM) family the most famous ones. A recent development uses deterministic "suffix automata" to design new optimal string matching algorithms, e.g. BDM and TurboBDM. Flexibility has been addressed quite separately by the use of "bit-parallelism", which simulates automata in their nondeterministic form by using bits and exploiting the intrinsic parallelism inside the computer word, e.g. the Shift-Or algorithm. Those algorithms are extended to handle classes of characters and errors in the pattern and/or in the text, their drawback being their inability to skip text characters. In this paper we merge bit-parallelism and suffix automata, so that a nondeterministic suffix automaton is simulated using bit-parallelism. The resulting algorithm, called BNDM, obtains the best from both worlds. It is much simpler to implement than BDM and nearly as simple as Shift-Or. It inherits from Shift-Or the ability to handle flexible patterns and from BDM the ability to skip characters. BNDM is 30%-40% faster than BDM and up to 7 times faster than Shift-Or. When compared to the fastest existing algorithms on exact patterns (which belong to the BM family), BNDM is from 20% slower to 3 times faster, depending on the alphabet size. With respect to flexible pattern searching, BNDM is by far the fastest technique to deal with classes of characters and is competitive to search allowing errors. In particular, BNDM seems very adequate for computational biology applications, since it is the fastest algorithm to search on DNA sequences and flexible searching is an important problem in that area. As a theoretical development related to flexible pattern matching, we introduce a new automaton to recognize suffixes of patterns with classes of characters. To the best of our knowledge, this automaton has not been studied before.

The Total Correctness of Parallel Programs

We describe a formal theory of the total correctness of parallel programs, including such heretofore theoretically incomplete properties as safety from deadlock and starvation under fair-scheduling. We present a sound and complete set of proof rules for the total correctness of parallel programs expressed in nondeterministic form. The proof of soundness and completeness is novel in that we show that the weakest pre-conditions for the correctness criteria are actually fixed-points (least or greatest) of continuous functions over the complete lattice of total predicates. We have obtained proof rule schemata which can universally be applied to least or greatest fixed-points of continuous functions. Therefore, a system of proof rules is a priori sound and complete once it is shown that certain weakest pre-conditions are extremum fixed-points. The relationship between true parallelism and nondeterminism is also discussed.