A central question in the Japanese high vowel devoicing literature concerns whether vowels are devoiced through a categorical process or via gradient reduction. Examining how vowel height and consonantal voicing condition phrase-internal CV duration in a corpus of spontaneous Tokyo Japanese, it was found that CVs containing high vowels are substantially shorter before voiceless consonants, whilst non-high vowels do not exhibit comparable shortening. This quantitative difference between CV durations suggests a controlled temporal compression of the CV, consistent with views (...) that Japanese vowel devoicing is produced through a categorical process targeting high vowels preceding voiceless consonants, and supports previous observations made of elicited productions. (shrink)

Natural language involves both speaking and listening. Recent models claim that production and comprehension share aspects of processing and are linked within individuals (Dell & Chang, 2014; MacDonald, 2013; Pickering & Garrod, 2004; 2013a). Evidence for this claim has come from studies of cross-modality structural priming, mainly examining processing in the direction of comprehension to production. The current study replicated these comprehension to production findings and developed a novel cross-modal structural priming paradigm from production to comprehension using a temporally-sensitive online (...) measure of comprehension, Event-Related Potentials. For Comprehension-to-Production priming, participants first listened to active or passive sentences and then described target pictures using either structure. In Production-to-Comprehension priming, participants first described a picture using either structure and then listened to target passive sentences while EEG was recorded. Comprehension-to-Production priming showed the expected passive sentence priming for syntactic choice, but not response time or average syllable duration. In Production-to-Comprehension priming, primed, versus unprimed, passive sentences elicited a reduced N400. These effects support the notion that production and comprehension share aspects of processing and are linked within the individual. Moreover, this paradigm can be used for the exploration priming at different linguistic levels as well as the influence of extra-linguistic factors on natural language use. (shrink)

A prerequisite for spoken language learning is segmenting continuous speech into words. Amongst many possible cues to identify word boundaries, listeners can use both transitional probabilities between syllables and various prosodic cues. However, the relative importance of these cues remains unclear, and previous experiments have not directly compared the effects of contrasting multiple prosodic cues. We used artificial language learning experiments, where native German speaking participants extracted meaningless trisyllabic “words” from a continuous speech stream, to evaluate these factors. We compared (...) a baseline condition to five test conditions, in which word-final syllables were either followed by a pause, lengthened, shortened, changed to a lower pitch, or changed to a higher pitch. To evaluate robustness and generality we used three tasks varying in difficulty. Overall, pauses and final lengthening were perceived as converging with the statistical cues and facilitated speech segmentation, with pauses helping most. Final-syllable shortening hindered baseline speech segmentation, indicating that when cues conflict, prosodic cues can override statistical cues. Surprisingly, pitch cues had little effect, suggesting that duration may be more relevant for speech segmentation than pitch in our study context. We discuss our findings with regard to the contribution to speech segmentation of language-universal boundary cues vs. language-specific stress patterns. (shrink)

Temporal regularities in speech, such as interdependencies in the timing of speech events, are thought to scaffold early acquisition of the building blocks in speech. By providing on-line clues to the location and duration of upcoming syllables, temporal structure may aid segmentation and clustering of continuous speech into separable units. This hypothesis tacitly assumes that learners exploit predictability in the temporal structure of speech. Existing measures of speech timing tend to focus on first-order regularities among adjacent units, and are (...) overly sensitive to idiosyncrasies in the data they describe. Here, we compare several statistical methods on a sample of 18 languages, testing whether syllable occurrence is predictable over time. Rather than looking for differences between languages, we aim to find across languages (using clearly defined acoustic, rather than orthographic, measures), temporal predictability in the speech signal which could be exploited by a language learner. First, we analyse distributional regularities using two novel techniques: a Bayesian ideal learner analysis, and a simple distributional measure. Second, we model higher-order temporal structure—regularities arising in an ordered series of syllable timings—testing the hypothesis that non-adjacent temporal structures may explain the gap between subjectively-perceived temporal regularities, and the absence of universally-accepted lower-order objective measures. Together, our analyses provide limited evidence for predictability at different time scales, though higher-order predictability is difficult to reliably infer. We conclude that temporal predictability in speech may well arise from a combination of individually weak perceptual cues at multiple structural levels, but is challenging to pinpoint. (shrink)

English second language learners often experience difficulties in producing native-like English lexical stress. It is unknown which acoustic correlates, such as fundamental frequency (F0), duration, and intensity, are the most problematic for Chinese dialect speakers. The present study investigated the prosodic transfer effects of first language (L1) regional dialects on the production of English stress contrasts. Native English speakers (N = 20) and Chinese learners (N = 60) with different dialect backgrounds (Beijing, Changsha, and Guangzhou dialects) produced the same (...) stimulus including both trochaic and iambic patterns. Results showed that (a) all participants produced the stressed syllable with greater values of F0, duration, and intensity; (b) Native speakers of English employed an exquisite combination of F0, duration, and intensity, while the dialect groups transfer their native prosody into their production of English lexical stress, resulting in the deviation or abnormality of acoustic cues. Results suggest that L1 native dialect background is considered as a potentially influential factor which may transfer in L2 speech encoding and decoding process. (shrink)

Equimetrical translation of verse, which conveys the metre of the source text, should be distinguished from equiprosodic translation of verse, which conveys theversification system of the source text. Equiprosodic translation of verse can rely on the possibilities of natural language (for instance, when presumably Publius Baebius Italicus created the Ilias Latina, he made use of the quantitative structure in Latin), but it can also employ an artificial system (cf., for example, the quantitative verse in Church Slavonic or English). The Estonian (...) language makes it possible to convey the syllabic (based on the number of syllables), accentual (based on the number and configuration of accents) and quantitative (based on the configuration of durations) versification systems. In practice, combined types are most frequent, for instance, the ones in which both the syllable count and the configuration of accents is relevant; in Estonian, versification systems with theparticipation of all three principles are possible as well. Despite the contrast of quantity in Estonian, the transmission of the quantitative structure of ancient metrics still involves a number of difficulties which result from differences in the prosodic structures. The transmission of purely syllabic versification system has also been problematic: it is hard to perceive such structure as verse in Estonian and therefore it has often been conveyed with the help of different syllabic-accentual or accentual-syllabic verse metres. Although equiprosodic translation is not necessarily equimetrical, in actual translation practice it usually is so. (shrink)

Auditory feedback perturbation studies have indicated a link between feedback and feedforward mechanisms in speech production when participants compensate for applied shifts. In spectral perturbation studies, speakers with a higher perceptual auditory acuity typically compensate more than individuals with lower acuity. However, the reaction to feedback perturbation is unlikely to be merely a matter of perceptual acuity but also affected by the prediction and production of precise motor action. This interplay between prediction, perception, and motor execution seems to be crucial (...) for the timing of speech and non-speech motor actions. In this study, to examine the relationship between the responses to temporally perturbed auditory feedback and rhythmic abilities, we tested 45 adult speakers on the one hand with a temporal auditory feedback perturbation paradigm, and on the other hand with rhythm perception and production tasks. The perturbation tasks temporally stretched and compressed segments (onset + vowel or vowel + coda) in fluent speech in real-time. This technique sheds light on the temporal representation and the production flexibility of timing mechanisms in fluent speech with respect to the structure of the syllable. The perception tasks contained staircase paradigms capturing duration discrimination abilities and beat-alignment judgments. The rhythm production tasks consisted of finger tapping tasks taken from the BAASTA tapping battery and additional speech tapping tasks. We found that both auditory acuity and motor stability in finger tapping affected responses to temporal auditory feedback perturbation. In general, speakers with higher auditory acuity and higher motor variability compensated more. However, we observed a different weighting of auditory acuity and motor stability dependent on the prosodic structure of the perturbed sequence and the nature of the response as purely online or adaptive. These findings shed light on the interplay of phonological structure with feedback and feedforward integration for timing mechanisms in speech. (shrink)

A model of gestural sequencing in speech is proposed that aspires to producing biologically plausible fluent and efficient movement in generating an utterance. We have previously proposed a modification of the well-known task dynamic implementation of articulatory phonology such that any given articulatory movement can be associated with a quantification of effort (Simko & Cummins, 2010). To this we add a quantitative cost that decreases as speech gestures become more precise, and hence intelligible, and a third cost component that places (...) a premium on the duration of an utterance. Together, these three cost elements allow us to derive algorithmically optimal sequences of gestures and dynamical parameters for generating articulator movement. We show that the optimized movement displays many timing characteristics that are representative of real speech movement, capturing subtle details of relative timing between gestures. Optimal movement sequences also display invariances in timing that suggest syllable-level coordination for CV sequences. We explore the behavior of the model as prosodic context is manipulated in two dimensions: clarity of articulation and speech rate. Smooth, fluid, and efficient movements result. (shrink)

Mismatch negativity is the electroencephalographic waveform obtained by subtracting event-related potential responses evoked by unexpected deviant stimuli from responses evoked by expected standard stimuli. While the MMN is thought to reflect an unexpected change in an ongoing, predictable stimulus, it is unknown whether MMN responses evoked by changes in different stimulus features have different magnitudes, latencies, and topographies. The present study aimed to investigate whether MMN responses differ depending on whether sudden stimulus change occur in pitch, duration, location or (...) vowel identity, respectively. To calculate ERPs to standard and deviant stimuli, EEG signals were recorded in normal-hearing participants who listened to roving oddball sequences of artificial syllables. In the roving paradigm, any given stimulus is repeated several times to form a standard, and then suddenly replaced with a deviant stimulus which differs from the standard. Here, deviants differed from preceding standards along one of four features. The feature levels were individually chosen to match behavioral discrimination performance. We identified neural activity evoked by unexpected violations along all four acoustic dimensions. Evoked responses to deviant stimuli increased in amplitude relative to the responses to standard stimuli. A univariate analysis yielded no significant differences between MMN responses following violations of different features. However, in a multivariate analysis, acoustic features could be decoded from the topography of mismatch responses, although at later latencies than those typical for MMN. These results support the notion that deviant feature detection may be subserved by a different process than general mismatch detection. (shrink)

The phonetic evolution of the Greek language which, towards the end of the Hellenistic period, substituted for the quantitative rhythm, based on the opposition of duration of the syllables, a rhythm based on the distance between stressed syllables, allowed the emergence of new poetic processes which followed after the traditional metrics: the equality of number of accents between several cola and the echoes between stress-related clausulae. The analysis of some of Alciphro’s bucolic letters from this point of view reveals (...) that they are sorts of poèmes en prose organized in isotonic stanzas, with isotony of cola and recurring clausulae in close echoes. This discovery reveals the really artistic character of these letters. It also supplies a criterion of choice between variants or conjectures when the text is corrupted. (shrink)

Are there illusions of duration? Certainly, many experiences of an event’s duration differ from its measure in clock duration, the measure of that event in seconds, minutes, hours, and so forth. However, I argue that an illusory duration requires more than difference from a real duration; it requires difference from a duration that is relevant to experience. It is plausible to hold that there are many kinds of real duration and reason to question (...) the relevance of all of them. In particular, the interpretation of experienced duration as illusory is typical because it is compared to clock time; the experience of duration goes wrong by being different from a clock measurement of duration. However, I argue that clock duration is not obviously relevant to evaluating the experience of duration.In response, one might hold that it is plausible to evaluate experience by clock duration because clocks more closely match reality than experiences do; on the scale of experience, clock time is no different to real duration. It is not that experienced duration is an illusion because it is merely different from clock duration; it is an illusion because it is different from real duration and we know this because of its difference from clock duration. It is like illusions of size: some object seems to be a size it is not and we know this by comparing it to an object we can otherwise accurately measure by meters.However, unlike size illusions, it is not clear what the ‘real duration’ is against which we should evaluate apparent duration. What is meant by ‘real duration’ involves either an appeal to the duration of substantial absolute time or some kind of duration in things, for example, duration which is the measure of change in some kind of process. is an irrelevant duration; few positions hold that we experience absolute time. As for, if real duration is a measure of change, then, for experienced duration to match clock duration, they must both agree on the relevant change. If there is a difference in what is treated as the real duration, then neither experience nor clocks can be treated as evaluable in terms of the other.Finally, we may have an illusory duration because there are cases of variation between experiences of the same duration. Yet, even here, we may be misled; we may not be directly comparing experiences. We compare the experienced durations through first measuring each in terms of clock duration. If there is a variability in the relationship between clock standard and some relevant standard for experience, then one expects anything accurately meeting one standard to differ from anything accurately meeting the other. The error is holding there is a stable relationship between the standards. This error is not a matter of our experience of duration, and so is not an illusion of duration. (shrink)

Bergson's central contention is that time is not measurable by any objective standard; in Duration and Simultaneity, that position is tried out against the major movement in physics of the day - Relativity. Bergson argues that Relativity fails to live up to the promise of a truly relative physics, and counter to its own spirit retains some of the objectivist assumptions of previous world views. Duration and Simultaneity was conceived in the desire to make good the new paradigm (...) to which Relativity was bound to lay claim; in the desire to be more Einsteinian than Einstein. (shrink)

Professor Tucker in the C.R. vol. xi. pp. 341 sqq. has revolutionized our notions of ‘doubtful syllables’: we have now learned that such syllables are normally short, and that lengthening is the licence.

Some of the most salient differences among Arabic vernaculars have to do with syllable structure. This study focuses on the syllabification patterns of three dialect groups, (1) VC-dialects, (2) C-dialects, and (3) CV-dialects,1 and argues that they differ in the licencing of SEMISYLLA- BLES, moras unaffiliated with syllables and adjoined to higher prosodic constituents. The analysis provides some evidence for a constraint-based version of Lexical Phonology, which treats word phonology and sentence phonology as distinct constraint systems which interact in (...) serial fashion. (shrink)

In ancient Greek, the pitch accent of most words depends on the syllabification assigned to underlying representations, while a smaller, morphologically identifiable class of derived words is accented on the basis of the surface syllable structure, which results from certain contraction and deletion processes. Noyer 1997 proposes a cyclic analysis of these facts and argues that they are incompatible with parallel OT assumptions. His central claim is that the pre-surface syllabification to which accent is assigned in the bulk of (...) the Greek vocabulary does not occur at a “level privileged by UG,” such as the word level or the “cycle-final” level, but simply at an arbitrary point in the derivation.. The implication is that extrinsic rule ordering is required to do justice to the accent system. Thus, Noyer’s work presents a challenge to any version of OT phonology. In this paper, I take up the challenge and argue that, although fully parallel OT may not be up to dealing with these accentual facts, the stratal version of OT based on Lexical Phonology and Phonology provides a much better analysis of them than phonology with ordered rules does. (shrink)

A classic problem in cognitive science concerns how listeners perceive and understand speech as comprised of discrete words. We propose a Syllable Inference account of spoken word recognition and segmentation, under which alternative hierarchical models of syllables, words, and phonemes are dynamically posited from cues that include current and past speech rate, with a goal of maximal prediction of sensory input. Three experiments using the Visual World eye‐tracking paradigm provide evidence supporting our proposal.

Professor Tucker in the C.R. vol. xi. pp. 341 sqq. has revolutionized our notions of ‘doubtful syllables’: we have now learned that such syllables are normally short, and that lengthening is the licence.

In ‘Location and Perdurance’ (2010), I argued that there are no compelling mereological or sortal grounds requiring the perdurantist to distinguish the molecule Abel from the atom Abel in Gilmore’s original case (2007). The remaining issue Gilmore originally raised concerned the ‘mass history’ of Adam and Abel, the distribution of ‘their’ mass over spacetime. My response to this issue was to admit that mass histories needed to be relativised to a way of partitioning the location of Adam/Abel, but that did (...) not amount to relativising any fundamental natural intrinsic properties—the latter are all had unrelativised, and (so most perdurantists would say). (shrink)

Relationships between phonological and morphological complexity have long been proposed in the linguistic literature, with empirical investigations often seeking complexity trade-offs. Positive complexity correlations tend not to be viewed in terms of motivations. We argue that positive complexity correlations can be diachronically well-motivated, emerging from crosslinguistically prevalent processes of language change. We examine the correlation between syllable complexity and morphological synthesis, hypothesizing that the process of grammaticalization motivates a positive relationship between the two features. To test this, we conduct (...) a typological survey of 95 diverse languages and a corpus study of 21 languages with substantive corpora from the DoReCo project. The first study establishes a significant positive correlation between syllable complexity, measured in terms of maximal syllable patterns, and the index of synthesis. The second study tests the hypothesis that the relationship between syllable complexity and synthesis holds at local levels and within noun and verb types, as predicted by a grammaticalization account. While the findings of the corpus study are limited in their statistical power, the observed tendencies are consistent with our predictions. This study contributes important findings to the complexity literature, as well as a novel method which incorporates broad typological sampling and deep corpus analysis. (shrink)

Perception of time is susceptible to distortions; among other factors, it has been suggested that the perceived duration of a stimulus is affected by the observer’s expectations. It has been hypothesized that the duration of an oddball stimulus is overestimated because it is unexpected, whereas repeated stimuli have a shorter perceived duration because they are expected. However, recent findings suggest instead that fulfilled expectations about a stimulus elicit an increase in perceived duration, and that the oddball (...) effect occurs because the oddball is a target stimulus, not because it is unexpected. Therefore, it has been suggested that top-down attention is sometimes sufficient to explain this effect, and sometimes only necessary, with an additional contribution from saliency. However, how the expectedness of a target stimulus and its salient features affect its perceived duration is still an open question. In the present study, participants’ expectations about and the saliency of target stimuli were orthogonally manipulated with stimuli presented on a short (Experiment 1) or long (Experiment 2) temporal scale. Four repetitive standard stimuli preceded each target stimulus in a task in which participants judged whether the target was longer or shorter in duration than the standards. Engagement of top-down attention to target stimuli increased their perceived duration to the same extent irrespective of their expectedness. A small but significant additional contribution to this effect from the saliency of target stimuli was dependent on the temporal scale of stimulus presentation. In Experiment 1, saliency only significantly increased perceived duration in the case of expected target stimuli. In contrast, in Experiment 2, saliency exerted a significant effect on the overestimation elicited by unexpected target stimuli, but the contribution of this variable was eliminated in the case of expected target stimuli. These findings point to top-down attention as the primary cognitive mechanism underlying the perceptual extraction and processing of task-relevant information, which may be strongly correlated with perceived duration. Furthermore, the scalar properties of timing were observed, favoring the pacemaker-accumulator model of timing as the underlying timing mechanism. (shrink)

What is the nature of time? This new study engages with the philosophy of Henri Bergson on time and proposes a new way of thinking about the effects of future events on the past. According to Bergson, time is an integral feature of real things, just as much as their material or size. When a flower grows, it takes a period of real time for it to flourish, which cannot be quickened or slowed down, nor can it be eliminated from (...) the process of growth. Bergson named this real time 'duration' and argued that everything and everyone exist as duration, and that internal processes flow into one another, with no clear boundaries that separate one phase of duration from another. According to Bergson's philosophy, the past does not disappear but smoothly flows into the present, forming an indivisible dynamic unity. But what if the causal flow of temporal reality is not unidirectional? What if not only past events influence future ones, but future ones in their turn have retrospective effect on past occurrences? The author of this book analyses these key questions, asserts that the changeability of the past follows from Bergson's theory of time and proposes a theory of embodied time that involves the retrospective enrichment of reality. (shrink)

The purpose of this article is to show a structural relationship in Dutch between sentences with the main verb "duren" (last) and specifying complements such as een week (a week) or "drie kwartier" (three quarters of an hour) on the one hand, and sentences with Duration Measuring Adverbials such as "gedurende een week" (for a week), "gedurende die week" (lit: for that week) on the other.

This book studies various perspectives in the history of European philosophy on the relationship between time and movement. Ever since the pre-Socratic thinker Zeno of Elea linked time and space to understand bodily movement, his so-called paradoxes of motion have remained unsolved. One of his most important critics, the French philosopher Henri Bergson, criticized the usual connection between time and space and established a new way of understanding time as duration (durée). Whereas Zeno presented an objectivist understanding of time, (...) Bergson emphasized its subjectivist meaning. Both contradictory positions seem incompatible, referring to pure intellect (Zeno) on the one hand or pure sensation (Bergson) on the other. Looking at Hegel's Phenomenology, this book shows that the outer and inner consciousness of time became crucial to his principle of movement and change. In his view, time is an integral part of dialectical processes that are historically substantiated. Hegel sought to subordinate pure concepts and ideas so that they would become indispensable moments of the self knowing spirit. Cassirer appreciated the idealism of coming into being but rejected Hegel's concept of the absolute. Instead, he established his philosophy of symbolic forms, in which the development of different perceptions and conceptions of time - from situational affective experience to the mathematical system of relations - determines the direction of the symbolic formation process. In the end, the sensitive concept of time is replaced by the relational concept of natural numbers, in which all here-and-now experiences are embedded. Finally, Bourdieu attempts to reintegrate symbolic forms into social processes. The book reflects on the concepts mentioned here by discussing their pros and cons in order to shed more light on the relationship between time and movement in European thought. (shrink)

Wearing facial masks became a common practice worldwide during the COVID-19 pandemic. This study investigated (1) whether facial masks that cover adult faces affect 4- to 6-year-old children’s recognition of emotions in those faces and (2) whether the duration of children’s exposure to masks is associated with emotion recognition. We tested children from Switzerland (N = 38) and Brazil (N = 41). Brazil represented longer mask exposure due to a stricter mandate during COVID-19. Children had to choose a face (...) displaying a specific emotion (happy, angry, or sad) when the face wore either no cover, a facial mask, or sunglasses. The longer hours of mask exposure were associated with better emotion recognition. Controlling for the hours of exposure, children were less likely to recognise emotions in partially hideen faces. Moreover, Brazilian children were more accurate in recognising happy faces than Swiss children. Overall, facial masks may negatively impact children’s emotion recognition. However, prolonged exposure appears to buffer the lack of facial cues from the nose and mouth. In conclusion, restricting facial cues due to masks may impair kindergarten children’s emotion recognition in the short run. However, it may facilitate their broader reading of facial emotional cues in the long run. (shrink)

Variation in the durations of exclusive breastfeeding (exBF) and any breastfeeding (anyBF) is associated with socioecological factors. This plasticity in breastfeeding behavior appears adaptive, but the mechanisms involved are unclear. With this concept in mind, we investigated whether durations of exBF and anyBF in a rural Maya population covary with markers of a form of socioecological change—market integration—and whether individual factors (individual learning, physiological plasticity) and/or learning from others in the community (social learning, norm adherence) mediate these changes. Using data (...) from 419 mother-child pairs from two Guatemalan Maya villages, we fit a bivariate linear mixed model. The model compared exBF and anyBF among children from households of varying degrees of market integration whose mothers follow what we inferred to be local infant-feeding norms. It controlled for other factors expected to affect breastfeeding durations. We found evidence that exBF is associated with whether mothers follow their population’s infant feeding norms, but no evidence that exBF is associated with the household’s level of market integration. Conversely, anyBF is significantly associated with the household’s market integration, but not with the villages’ inferred norms. Because deviations from exBF norms are likely to result in infant mortality and reduced fitness, we hypothesize that the incentive to conform is relatively strong. Relatively greater individual plasticity in anyBF allows mother-child pairs to tailor it to socioecological conditions. Deviations from anyBF norms may be tolerated because they may provide later-life health/fitness payoffs, while posing few risks to infant survival. (shrink)

Research into Bergson’s philosophy downplays a key development in his first work, Time and free will. It is there that Bergson explicitly opposes himself to Kant by arguing that succession is not a temporal concept, but a spatial one. This is the crucial point of departure for Bergson’s entire philosophy, one that allows him to radically dismiss Kant’s notion of freedom in favor of one based on duration and multiplicity. This text has two aims. Firstly to add to Bergson (...) scholarship by explicating the structure and force of Bergson’s initial argument against Kant, demonstrating that his engagement with Kant is much less incremental than has been suggested in secondary literature. Secondly, to reconstruct the consequences regarding freedom that Bergson immediately draws in departing from Kant, which illustrates the profundity and originality of his thought at the very inception of his oeuvre. (shrink)

The cyclic nature of speech production, as manifested in the syllabic organization of spoken language, is likely to reflect general properties of sensori-motor integration rather than merely a phylogenetic progression from mastication, teeth chattering, and lipsmacks. The temporal properties of spontaneous speech reflect the entropy of its underlying constituents and are optimized for rapid transmission and decoding of linguistic information conveyed by a complex constellation of acoustic and visual cues, suggesting that the dawn of human language may have occurred when (...) the articulatory cycle was efficiently yoked to the temporal dynamics of sensory coding and rapid retrieval from referential memory. (shrink)

To reason about continuous processes in some areas of artificial intelligence and embedded systems one has to express real-time properties. For such purpose a real-time logic has to be considered. Various such logics have been proposed. Some of these formalisms interpret formulas over intervals of time. These are called interval logics. Zhou Chaochen and Michael Hansen have introduced one such first-order interval logic called Neighborhood Logic (NL) which has two expanding modalities ◊r and ◊l. They have shown the adequacy of (...) these modalities by deriving other unary and binary modalities from them; in particular, they show that chop can be expressed in terms of these modalities. The logic is subsequently expanded to get a Duration Calculus (called DC/nl) by expressing temporal variables as integrals of state variables. Liveness and fairness properties of a computing system can now be expressed in DC/nl by means of neighborhood (expanding) modalities. We take up an investigation of DC/nl in detail. We present a proof system for it. We further show that most of the results that hold in the original Duration Calculus continue to hold in our logic with some modifications. In this process we discuss soundness, completeness, and decidability results for DC/nl. Thus this paper establishes DC/nl as a useful formalism for specifying and verifying properties of real-time computing systems. (shrink)

I argue in this paper that Descartes's goal with his doctrine of the continuous recreation of the world is to offer a unified and ultimate causal explanation for the possibility of motion and duration in the world, the permanence of created things, and the continuation of their motion and duration. This unified explanation seems to be the only one which, according to Descartes, satisfies the two basic requirements any ultímate cause should meet: the cause must be active and (...) not being in motion itself. God's recreations of the world is Descartes's solution to this search. I also show in this article, on the one hand, that this doctrine successfully overcomes, in particular, the four major conflicts which threaten its consistency, and, on the other, the new meaning which the laws of nature acquire under the doctrine of the continuous recreation of the world. /// En este artículo defiendo que la pretensión principal de Descartes al proponer la doctrina de la recreación continua del mundo es encontrar una explicación unificada y última de la posibilidad de movimiento y duración en el mundo, de la permanencia de las cosas creadas y de la continuación del movimiento. Esta explicación unificada es la única que, según Descartes, satisface los dos requisitos que parece buscar en la explicación causal última del movimiento: la causa debe ser activa y no debe estar ella misma en movimiento. Las recreaciones del mundo constituyen esa causa. Por una parte, también muestro cómo esta solución supera, en concreto, los cuatro conflictos mayores que amenazan su consistencia, y, por otra, el nuevo significado que las leyes de la naturaleza adquieren en consonancia con esta doctrina de la recreación continua del mundo. (shrink)