Multi-core Code Generation from Polychronous Programs with Time-Predictable Properties (ACVI 2014)

Workshop of ACM/IEEE 17th International Conference on Model Driven Engineering Languages and Systems (MoDELS 2014)International audienceSynchronous programming models capture concurrency in computation quite naturally, especially in its dataflow multi-clock (polychronous) flavor. With the rising importance of multi-core processors in safety-critical embedded systems or cyber-physical systems (CPS), there is a growing need for model-driven generation of multi-threaded code for multi-core systems. This paper proposes a build method of timepredictable system on multi-core, based on synchronous-model development. At the modeling level, the synchronous abstraction allows deterministic time semantics. Thus synchronous programming is a good choice for time-predictable system design. At the compiler level, the verified compiler from the synchronous language SIGNAL to our intermediate representation (S-CGA, a variant of guarded actions) and to multi-threaded code, preserves the time predictability. At the platform level, we propose a time-predictable multi-core architecture model in AADL (Architecture Analysis and Design Language), and then we map the multi-threaded code to this model. Therefore, our method integrates time predictability across several design layers

The Origins of Computational Mechanics: A Brief Intellectual History and Several Clarifications

The principle goal of computational mechanics is to define pattern and structure so that the organization of complex systems can be detected and quantified. Computational mechanics developed from efforts in the 1970s and early 1980s to identify strange attractors as the mechanism driving weak fluid turbulence via the method of reconstructing attractor geometry from measurement time series and in the mid-1980s to estimate equations of motion directly from complex time series. In providing a mathematical and operational definition of structure it addressed weaknesses of these early approaches to discovering patterns in natural systems. Since then, computational mechanics has led to a range of results from theoretical physics and nonlinear mathematics to diverse applications---from closed-form analysis of Markov and non-Markov stochastic processes that are ergodic or nonergodic and their measures of information and intrinsic computation to complex materials and deterministic chaos and intelligence in Maxwellian demons to quantum compression of classical processes and the evolution of computation and language. This brief review clarifies several misunderstandings and addresses concerns recently raised regarding early works in the field (1980s). We show that misguided evaluations of the contributions of computational mechanics are groundless and stem from a lack of familiarity with its basic goals and from a failure to consider its historical context. For all practical purposes, its modern methods and results largely supersede the early works. This not only renders recent criticism moot and shows the solid ground on which computational mechanics stands but, most importantly, shows the significant progress achieved over three decades and points to the many intriguing and outstanding challenges in understanding the computational nature of complex dynamic systems.Comment: 11 pages, 123 citations; http://csc.ucdavis.edu/~cmg/compmech/pubs/cmr.ht

Using the predictability criterion for selecting extended verbs for Shona dictionaries

The paper examines the "predictability criterion", a classificatory tool which is used in selecting affixed word forms for dictionary entries. It focuses on the criterion as it has been used by the African Languages Lexical (ALLEX) Project for selecting extended verbs to enter as headwords in the Project's first monolingual Shona dictionary Duramazwi ReChiShona. The article also examines the status of Shona verbal extensions in terms of their semantic input to the verb stems they are attached to. The paper was originally motivated by two observations: (a) that predictability seems to be a matter of degree; and (b) that the predictability criterion tended to be used inconsistently in the selection of extended verbs and senses for Duramazwi ReChiShona. An analysis of 412 productively extended verbs that were entered as headwords in Duramazwi ReChiShona shows that verbal extensions can bring both predictable and unpredictable senses to the verb stems they are attached to. The paper demonstrates that for an effective use of the predictability criterion for selecting extended verbs for Shona dictionaries, there is need for the lexicographer to have an in-depth understanding of the kinds of semantic movements that are caused when verb stems are extended. It shows the need to view verbal extensions in Shona as derivational morphemes, not inflectional morphemes as some earlier scholars have concluded.Keywords: definition; derivational morpheme; dictionary; dictionary entry; lexeme; lexicography; morphology; predictability criterion; semantics; shona; verb stem; verbal extension

Eight Dimensions for the Emotions

The author proposes a dimensional model of our emotion concepts that is intended to be largely independent of one’s theory of emotions and applicable to the different ways in which emotions are measured. He outlines some conditions for selecting the dimensions based on these motivations and general conceptual grounds. Given these conditions he then advances an 8-dimensional model that is shown to effectively differentiate emotion labels both within and across cultures, as well as more obscure expressive language. The 8 dimensions are: (1) attracted—repulsed, (2) powerful—weak, (3) free—constrained, (4) certain—uncertain, (5) generalized—focused, (6) future directed—past directed, (7) enduring—sudden, (8) socially connected—disconnected

Stress and stem allomorphy in the Romance perfectum: emergence, typology, and motivations of a symbiotic relation

Perfective stem allomorphy and stress are morphological traits which interact in complex ways in Romance verbal inflection. This article surveys the whole range of variation of these traits across Romance varieties, typologizes the observed interactions between the two, and examines attested and unattested possibilities. A comparison between the modern-day and the original Latin systems suggests that there is a strong pan-Romance bias against having verbs with a concrete combination of properties: perfective root-stress and no perfective stem alternation. This is a combination of traits that would have frequently resulted in diagonal syncretisms between past and present given the phonological changes attested in the daughter languages. Homophony avoidance (and the adaptive-discriminative role of morphology more generally) are therefore argued to motivate the observed bias. Keywords: change biases; diachrony; homophony; morphology; predictability; syncretis