Towards Symbolic State Traversal for Efficient WCET Analysis of Abstract Pipeline and Cache Models

Static program analysis is a proven approach for obtaining safe and tight upper bounds on the worst-case execution time (WCET) of program tasks. It requires an analysis on the microarchitectural level, most notably pipeline and cache analysis. In our approach, the integrated pipeline and cache analysis operates on sets of possible abstract hardware states. Due to the growth of CPU complexity and the existence of timing anomalies, the analysis must handle an increasing number of possible abstract states for each program point. Symbolic methods have been proposed as a way to reduce memory consumption and improve runtime in order to keep pace with the growing hardware complexity. This paper presents the advances made since the original proposal and discusses a compact representation of abstract caches for integration with symbolic pipeline analysis

Integrating Abstract Caches with Symbolic Pipeline Analysis

Static worst-case execution time analysis of real-time tasks is based on abstract models that capture the timing behavior of the processor on which the tasks run. For complex processors, task-level execution time bounds are obtained by a state space exploration which involves the abstract model and the program. Partial state space exploration is not sound. Symbolic methods using binary decision diagrams (BDDs) allow for a full state space exploration of the pipeline, thereby maintaining soundness. Caches are too large to admit an efficient BDD representation. On the other hand, invariants of the cache state can be computed efficiently using abstract interpretation. How to integrate abstract caches with symbolic-state pipeline analysis is an open question. We propose a semi-symbolic domain to solve this problem. Statistical data from industrial-level software and WCET tools indicate that this new domain will enable an efficient analysis

n-Aldehydes ( C 6 - C 10 ) in snow samples collected at the high alpine research station Jungfraujoch during CLACE 5

Samples of freshly fallen snow were collected at the high alpine research station Jungfraujoch, Switzerland, during the Cloud and Aerosol Characterization Experiments (CLACE) 5 in February and March 2006. Sampling was carried out on the Sphinx platform. Headspace-solid-phase-dynamic extraction (HS-SPDE) combined with gas chromatography/mass spectrometry (GC/MS) was used to quantify C6–C10 n-aldehydes in the snow samples. The most abundant n-aldehyde was n-hexanal (median concentration 1.324 micro g L -1) followed by n-nonanal, n-decanal, n-octanal and n-heptanal (median concentrations 1.239, 0.863, 0.460, and 0.304 micro g L -1, respectively). A wide range of concentrations was found among individual snow samples, even for samples taken at the same time. Higher median concentrations of all n-aldehydes were observed when air masses reached Jungfraujoch from the north-northwest in comparison to air masses arriving from the southeast-southwest. Results suggest that the n-aldehydes detected most likely are of direct and indirect biogenic origin, and that they entered the snow through the particle phase

La phonologie des exclamations en anglais

À partir d’un corpus d’enregistrements de répliques de la pièce de Tennessee Williams A Streetcar Named Desire, cet article traite de la phonologie des énoncés exclamatifs. Il établit que les spécificités phonologiques essentielles des exclamations sont de nature suprasegmentale et se trouvent être observées au niveau intonatif. Après avoir identifié certaines caractéristiques récurrentes des contours mélodiques observés dans les énoncés exclamatifs et montré que celles-ci sont conditionnées par la motivation sémantique et l’iconicité de l’intonation, nous nous intéressons aux liens indirects qui existent entre l’intonation des exclamations et l’expression du degré. Nous fondant sur une réflexion sur la fonction démarcative de l’intonation et la valeur illocutoire des énoncés exclamatifs, nous suggérons également que l’étude de l’intonation des exclamations est susceptible d’éclairer la notion d’acte d’énonciation en contexte d’interaction orale.Based on a corpus made up of recordings from Tennessee Williams’s play, A Streetcar Named Desire, this article investigates the phonology of exclamative utterances. It points out that the main characteristic phonological traits of exclamations are essentially suprasegmental and are to be observed at intonational level. After identifying some of the recurring characteristics of the intonation patterns used in exclamative utterances and showing that these can be explained by the fact that intonation is iconic and semantically motivated, this paper highlights the links between exclamation intonation and the expression of degree. Reflecting on the delimitative function of intonation and the illocutionary value of exclamations, it also suggests that the study of exclamative intonation sheds useful light on the nature of speech acts in spoken interactions

Tradition et changement phonétique dans une variété de contact : l’anglais de Lewis et Harris

La variété d’anglais parlée dans les Hébrides extérieures s’apparente, sur les plans grammatical et lexical, au Standard Scottish English (SSE). Sur les plan phonétique et phonologique, en revanche, elle diffère profondément de cette variété standard, en grande partie en raison de l’influence et de l’interférence du gaélique écossais.À partir de deux corpus d’enregistrements de locuteurs des îles de Lewis et Harris et d’observations réalisées ces seize dernières années dans les Hébrides extérieures, cet article propose une description des traits segmentaux et suprasegmentaux les plus saillants de l’accent hébridéen traditionnel.Un examen des caractéristiques du parler de certains adolescents de Lewis et Harris indique que plusieurs changements sont en cours dans les Hébrides extérieures, que ceux-ci résultent de la diffusion d’innovations phonétiques isolées ou de la disparition progressive des variantes les plus marquée, connue sous le terme de nivellement dialectal. Ces changements semblent favorisés à a fois par le déclin du gaélique et par l’attitude négative de certains jeunes hébridéens à l’égard des valeurs traditionnelles de la communauté insulaire. A partir de données recueillies auprès des adolescents et d’observations informelles, nous tentons d’identifier certains des traits les plus significatifs qui caractérisent l’évolution de l’accent de Lewis et Harris en temps apparent.From a grammatical and lexical point of view, the variety of English spoken in the Outer Hebrides is akin to Standard Scottish English (SSE). From a phonetic and phonological point of view, however, it is absolutely distinctive, mainly because of the influence and interference of Scottish Gaelic.Based on two corpora composed of recordings of speakers from Lewis and Harris as well as on informal observations collected in the Outer Hebrides during the past sixteen years, this paper identifies and describes the most salient traits of traditional Hebridean accents, be they segmental or prosodic.A brief examination of the speech of Hebridean adolescents highlights several changes in progress. These are to be traced both from the diffusion of individual phonetic innovations and from the attrition of marked variants – a phenomenon known as dialect levelling. These changes seem to be facilitated both by the decline of the Gaelic language and by the rejection of the traditional Hebridean values by a number of young speakers. Using data collected from adolescents as well as informal observations, we try to identify some of the most prominent changes that affect the accents of Lewis and Harris in apparent time

Are Smartwatches a Suitable Tool to Monitor Noise Exposure for Public Health Awareness and Otoprotection?

Introduction and Objectives: Noise-induced hearing loss (NIHL) and tinnitus are common problems that can be prevented with hearing protection measures. Sound level meters and noise dosimeters enable to monitor and identify health-threatening occupational or recreational noise, but are limited in their daily application because they are usually difficult to operate, bulky, and expensive. Smartwatches, which are becoming increasingly available and popular, could be a valuable alternative to professional systems. Therefore, the aim of this study was to evaluate the applicability of smartwatches for accurate environmental noise monitoring. Methods: The A-weighted equivalent continuous sound pressure level (LAeq) was recorded and compared between a professional sound level meter and a popular smartwatch. Noise exposure was assessed in 13 occupational and recreational settings, covering a large range of sound pressure levels between 35 and 110 dBA. To assess measurement agreement, a Bland-Altman plot, linear regression, the intra-class correlation coefficient, and descriptive statistics were used. Results: Overall, the smartwatch underestimated the sound level meter measurements by 0.5 dBA (95% confidence interval [0.2, 0.8]). The intra-class correlation coefficient showed excellent agreement between the two devices (ICC = 0.99), ranging from 0.65 (music club) to 0.99 (concert) across settings. The smartwatch’s sampling rate decreased significantly with lower sound pressure levels, which could have introduced measurement inaccuracies in dynamic acoustic environments. Conclusions: The assessment of ambient noise with the tested smartwatch is sufficiently accurate and reliable to improve awareness of hazardous noise levels in the personal environment and to conduct exploratory clinical research. For professional and legally binding measurements, we recommend specialized sound level meters or noise dosimeters. In the future, smartwatches will play an important role in monitoring personal noise exposure and will provide a widely available and cost-effective measure for otoprotection

In vivo visualization and analysis of 3-D hemodynamics in cerebral aneurysms with flow-sensitized 4-D MR imaging at 3T

Introduction: Blood-flow patterns and wall shear stress (WSS) are considered to play a major role in the development and rupture of cerebral aneurysms. These hemodynamic aspects have been extensively studied in vitro using geometric realistic aneurysm models. The purpose of this study was to evaluate the feasibility of in vivo flow-sensitized 4-D MR imaging for analysis of intraaneurysmal hemodynamics. Methods: Five cerebral aneurysms were examined using ECG-gated, flow-sensitized 4-D MR imaging at 3T in three patients. Postprocessing included quantification of flow velocities, visualization of time-resolved 2-D vector graphs and 3-D particle traces, vortical flow analysis, and estimation of WSS. Flow patterns were analyzed in relation to aneurysm geometry and aspect ratio. Results: Magnitude, spatial and temporal evolution of vortical flow differed markedly among the aneurysms. Particularly unstable vortical flow was demonstrated in a wide-necked parophthalmic ICA aneurysm (high aspect ratio). Relatively stable vortical flow was observed in aneurysms with a lower aspect ratio. Except for a wide-necked cavernous ICA aneurysm (low aspect ratio), WSS was reduced in all aneurysms and showed a high spatial variation. Conclusion: In vivo flow-sensitized 4-D MR imaging can be applied to analyze complex patterns of intraaneurysmal flow. Flow patterns, distribution of flow velocities, and WSS seem to be determined by the vascular geometry of the aneurysm. Temporal and spatial averaging effects are drawbacks of the MR-based analysis of flow patterns as well as the estimation of WSS, particularly in small aneurysms. Further studies are needed to establish a direct link between definitive flow patterns and different aneurysm geometrie