Interface-aware signal temporal logic

Safety and security are major concerns in the development of Cyber-Physical Systems (CPS). Signal temporal logic (STL) was proposedas a language to specify and monitor the correctness of CPS relativeto formalized requirements. Incorporating STL into a developmentprocess enables designers to automatically monitor and diagnosetraces, compute robustness estimates based on requirements, andperform requirement falsification, leading to productivity gains inverification and validation activities; however, in its current formSTL is agnostic to the input/output classification of signals, andthis negatively impacts the relevance of the analysis results.In this paper we propose to make the interface explicit in theSTL language by introducing input/output signal declarations. Wethen define new measures of input vacuity and output robustnessthat better reflect the nature of the system and the specification in-tent. The resulting framework, which we call interface-aware signaltemporal logic (IA-STL), aids verification and validation activities.We demonstrate the benefits of IA-STL on several CPS analysisactivities: (1) robustness-driven sensitivity analysis, (2) falsificationand (3) fault localization. We describe an implementation of our en-hancement to STL and associated notions of robustness and vacuityin a prototype extension of Breach, a MATLAB®/Simulink®toolboxfor CPS verification and validation. We explore these methodologi-cal improvements and evaluate our results on two examples fromthe automotive domain: a benchmark powertrain control systemand a hydrogen fuel cell system

The price of rapid exit in venture capital-backed IPOs

This paper proposes an explanation for two empirical puzzles surrounding initial public offerings (IPOs). Firstly, it is well documented that IPO underpricing increases during “hot issue” periods. Secondly, venture capital (VC) backed IPOs are less underpriced than non-venture capital backed IPOs during normal periods of activity, but the reverse is true during hot issue periods: VC backed IPOs are more underpriced than non-VC backed ones. This paper shows that when IPOs are driven by the initial investor’s desire to exit from an existing investment in order to finance a new venture, both the value of the new venture and the value of the existing firm to be sold in the IPO drive the investor’s choice of price and fraction of shares sold in the IPO. When this is the case, the availability of attractive new ventures increases equilibrium underpricing, which is what we observe during hot issue periods. Moreover, I show that underpricing is affected by the severity of the moral hazard problem between an investor and the firm’s manager. In the presence of a moral hazard problem the degree of equilibrium underpricing is more sensitive to changes in the value of the new venture. This can explain why venture capitalists, who often finance firms with more severe moral hazard problems, underprice IPOs less in normal periods, but underprice more strongly during hot issue periods. Further empirical implications relating the fraction of shares sold and the degree of underpricing are presented

Impactos ambientales del ciclo de vida de las baldosas cerámicas: análisis sectorial, identificación de estrategias de mejora y comunicación (I)

El artículo analiza el impacto ambiental que generan las baldosas cerámicas mediante el Análisis de Ciclo de Vida (AC) a nivel sectorial en el que participaron más de 50 empresas españolas. Los resultados han servido para la redacción de las Reglas de Categoría de Producto (RCP) para los recubrimientos de materiales cerámicos, necesarias para la edición de Declaraciones Ambientales de Producto. (Debido a la extensión del artículo recogeremos en esta edición la primera parte, correspondiente a la definición de objetivos y alcance del estudio y el análisis del inventario. La segunda parte, que consta de la evaluación de impactos e interpretación, la identificación de estrategias de mejora, la comunicación ambiental y las conclusiones se publicarán en el número 236 de Piscinas XXI).The article analyses the environmental impact of ceramic tiles by means of a sector-level Life Cycle Analysis (LCA) involving over 50 Spanish firms. The findings were then used to draw up the Product Category Rules (PCR) for ceramic coverings, which are needed to be able to issue Environmental Product Declarations. (Due to the length of the paper, in this edition we will include only the first part, which covers the definition of the aims and scope of the study, as well as the inventory analysis. The second part, which comprises the evaluation of the impacts and interpretation, the identification of the improvement strategies, environmental communication and the conclusions, will be published in issue 236 of Piscinas XXI.

Molecular dynamics approach: from chaotic to statistical properties of compound nuclei

Statistical aspects of the dynamics of chaotic scattering in the classical model of $\alpha$-cluster nuclei are studied. It is found that the dynamics governed by hyperbolic instabilities which results in an exponential decay of the survival probability evolves to a limiting energy distribution whose density develops the Boltzmann form. The angular distribution of the corresponding decay products shows symmetry with respect to $\pi/2$ angle. Time estimated for the compound nucleus formation ranges within the order of $10^{-21}$s.Comment: 11 pages, LaTeX, non

Paraphrastic Reformulations in Spoken Corpora

International audienceOur work addresses the automatic detection of paraphrastic reformulation in French spoken corpora. The proposed approach is syn-tagmatic. It is based on specific markers and the specificities of the spoken language. Manual multi-dimensional annotation performed by two annotators provides fine-grained reference data. An automatic method is proposed in order to decide whether sentences contain or not paraphras-tic relations. The obtained results show up to 66.4% precision. Analysis of the manual annotations indicates that few paraphrastic segments show morphological modifications (inflection, derivation or compounding) and that the syntactic equivalence between the segments is seldom respected, as these usually belong to different syntactic categories

Block of NMDA receptor channels by endogenous neurosteroids: implications for the agonist induced conformational states of the channel vestibule

N-methyl-D-aspartate receptors (NMDARs) mediate synaptic plasticity, and their dysfunction is implicated in multiple brain disorders. NMDARs can be allosterically modulated by numerous compounds, including endogenous neurosteroid pregnanolone sulfate. Here, we identify the molecular basis of the use-dependent and voltage-independent inhibitory effect of neurosteroids on NMDAR responses. The site of action is located at the extracellular vestibule of the receptor's ion channel pore and is accessible after receptor activation. Mutations in the extracellular vestibule in the SYTANLAAF motif disrupt the inhibitory effect of negatively charged steroids. In contrast, positively charged steroids inhibit mutated NMDAR responses in a voltage-dependent manner. These results, in combination with molecular modeling, characterize structure details of the open configuration of the NMDAR channel. Our results provide a unique opportunity for the development of new therapeutic neurosteroid-based ligands to treat diseases associated with dysfunction of the glutamate system

Be our guest/worker: reciprocal dependency and expressions of hospitality in Ni-Vanuatu overseas labour migration

Whilst there has been renewed interest in the development potential of temporary migration programmes, such schemes have long been criticized for creating conditions for exploitation and fostering dependence. In this article, which is based on a case study of Ni-Vanuatu seasonal workers employed in New Zealand’s horticultural industry, I show how workers and employers alike actively cultivate and maintain relations of reciprocal dependence and often describe their relation in familial terms of kinship and hospitality. Nevertheless, workers often feel estranged both in the Marxian sense of being subordinated to a regime of time-discipline, and in the intersubjective sense of feeling disrespected or treated unkindly. I show how attention to the ‘non-contractual element’ in the work contract, including expressions of hospitality, can contribute to anthropological debates surrounding work, migration, and dependence, and to interdisciplinary understandings of the justice of labour migration.ESRC scholarship (project reference ES/H034943/1