Book review: Acting Shakespeare’s language, by Andy Hinds

Book review: Acting Shakespeare’s language, by Andy Hinds. London: Oberon Books Ltd, 2015; ISBN: 9781783190089 (£14.99)Publisher PD

Lock-Free and Practical Deques using Single-Word Compare-And-Swap

We present an efficient and practical lock-free implementation of a concurrent deque that is disjoint-parallel accessible and uses atomic primitives which are available in modern computer systems. Previously known lock-free algorithms of deques are either based on non-available atomic synchronization primitives, only implement a subset of the functionality, or are not designed for disjoint accesses. Our algorithm is based on a doubly linked list, and only requires single-word compare-and-swap atomic primitives, even for dynamic memory sizes. We have performed an empirical study using full implementations of the most efficient algorithms of lock-free deques known. For systems with low concurrency, the algorithm by Michael shows the best performance. However, as our algorithm is designed for disjoint accesses, it performs significantly better on systems with high concurrency and non-uniform memory architecture

A BELIEF-DRIVEN DISCOVERY FRAMEWORK BASED ON DATA MONITORING AND TRIGGERING

A new knowledge-discovery framework, called Data Monitoring and Discovery Triggering (DMDT), is defined, where the user specifies monitors that âwatch" for significant changes to the data and changes to the user-defined system of beliefs. Once these changes are detected, knowledge discovery processes, in the form of data mining queries, are triggered. The proposed framework is the result of an observation, made in the previous work of the authors, that when changes to the user-defined beliefs occur, this means that, there are interesting patterns in the data. In this paper, we present an approach for finding these interesting patterns using data monitoring and belief-driven discovery techniques. Our approach is especially useful in those applications where data changes rapidly with time, as in some of the On-Line Transaction Processing (OLTP) systems. The proposed approach integrates active databases, data mining queries and subjective measures of interestingness based on user-defined systems of beliefs in a novel and synergetic way to yield a new type of data mining systems.Information Systems Working Papers Serie

Convergence and Divergence of Themes in Successful Psychotherapy: An Assimilation Analysis

Theme convergence is the linking of seemingly unrelated problem domains as they advance through assimilation stages-a developmental sequence of cognitive and affective changes through which problematic content is hypothesized to pass during successful psychotherapy. Theme divergence is the contradiction or conflict of solutions to different problems, so that progress in one domain leads to stagnation or regression in another domain. An intensive qualitative method called assimilation analysis was used to examine theme convergence and divergence in a successful psychodynamic psychotherapy with a 20–yr–old female patient. Because specific problems often fail to progress monotonically, even in successful psychotherapy cases, it is suggested that clients\u27 problems cannot be resolved in isolation; instead, they may influence each other toward resolution or stagnation in complex and unpredictable ways

Model view management with triple graph transformation systems

The final publication is available at Springer via http://dx.doi.org/10.1007/11841883_25Proceedings of Third International Conference, ICGT 2006 Natal, Rio Grande do Norte, Brazil, September 17-23, 2006In this paper, we present our approach for model view management in the context of Multi-View Visual Languages (MVVLs). These are made of a number of diagram types (or viewpoints) that can be used for the specification of the different aspects of a system. Therefore, the user can build different system views conform to the viewpoints, which are merged in a repository in order to perform consistency checking. In addition, the user can define derived views by means of graph query patterns in order to extract information from a base model (a system view or the repository). We have provided automatic mechanisms to keep synchronized the base model and the derived view when the former changes. Predefined queries by the MVVL designer result in so-called audience-oriented views. Finally, semantic views are used for analysing the system by its translation into a semantic domain. Our approach is based on meta-modelling to describe the syntax of the MVVL and each viewpoint, and on triple graph transformation systems to synchronize and maintain correspondences between the system views and the repository, as well as between the derived, audience-oriented and semantic views and the base models. We illustrate these concepts by means of an example in the domain of security for web systems.This work has been sponsored by the Spanish Ministry of Science and Education, projects TSI2005-08225-C07-06 and TSI2004-03394

New Solutions to the Firing Squad Synchronization Problems for Neural and Hyperdag P Systems

We propose two uniform solutions to an open question: the Firing Squad Synchronization Problem (FSSP), for hyperdag and symmetric neural P systems, with anonymous cells. Our solutions take e_c+5 and 6e_c+7 steps, respectively, where e_c is the eccentricity of the commander cell of the dag or digraph underlying these P systems. The first and fast solution is based on a novel proposal, which dynamically extends P systems with mobile channels. The second solution is substantially longer, but is solely based on classical rules and static channels. In contrast to the previous solutions, which work for tree-based P systems, our solutions synchronize to any subset of the underlying digraph; and do not require membrane polarizations or conditional rules, but require states, as typically used in hyperdag and neural P systems

Computational Complexity of Atomic Chemical Reaction Networks

Informally, a chemical reaction network is "atomic" if each reaction may be interpreted as the rearrangement of indivisible units of matter. There are several reasonable definitions formalizing this idea. We investigate the computational complexity of deciding whether a given network is atomic according to each of these definitions. Our first definition, primitive atomic, which requires each reaction to preserve the total number of atoms, is to shown to be equivalent to mass conservation. Since it is known that it can be decided in polynomial time whether a given chemical reaction network is mass-conserving, the equivalence gives an efficient algorithm to decide primitive atomicity. Another definition, subset atomic, further requires that all atoms are species. We show that deciding whether a given network is subset atomic is in $\textsf{NP}$, and the problem "is a network subset atomic with respect to a given atom set" is strongly $\textsf{NP}$-$\textsf{Complete}$. A third definition, reachably atomic, studied by Adleman, Gopalkrishnan et al., further requires that each species has a sequence of reactions splitting it into its constituent atoms. We show that there is a $\textbf{polynomial-time algorithm}$ to decide whether a given network is reachably atomic, improving upon the result of Adleman et al. that the problem is $\textbf{decidable}$. We show that the reachability problem for reachably atomic networks is $\textsf{Pspace}$-$\textsf{Complete}$. Finally, we demonstrate equivalence relationships between our definitions and some special cases of another existing definition of atomicity due to Gnacadja

Interrupt Timed Automata: verification and expressiveness

We introduce the class of Interrupt Timed Automata (ITA), a subclass of hybrid automata well suited to the description of timed multi-task systems with interruptions in a single processor environment. While the reachability problem is undecidable for hybrid automata we show that it is decidable for ITA. More precisely we prove that the untimed language of an ITA is regular, by building a finite automaton as a generalized class graph. We then establish that the reachability problem for ITA is in NEXPTIME and in PTIME when the number of clocks is fixed. To prove the first result, we define a subclass ITA- of ITA, and show that (1) any ITA can be reduced to a language-equivalent automaton in ITA- and (2) the reachability problem in this subclass is in NEXPTIME (without any class graph). In the next step, we investigate the verification of real time properties over ITA. We prove that model checking SCL, a fragment of a timed linear time logic, is undecidable. On the other hand, we give model checking procedures for two fragments of timed branching time logic. We also compare the expressive power of classical timed automata and ITA and prove that the corresponding families of accepted languages are incomparable. The result also holds for languages accepted by controlled real-time automata (CRTA), that extend timed automata. We finally combine ITA with CRTA, in a model which encompasses both classes and show that the reachability problem is still decidable. Additionally we show that the languages of ITA are neither closed under complementation nor under intersection