A Learning-Based Guidance Selection Mechanism for a Formally Verified Sense and Avoid Algorithm

This paper describes a learning-based strategy for selecting conflict avoidance maneuvers for autonomous unmanned aircraft systems. The selected maneuvers are provided by a formally verified algorithm and they are guaranteed to solve any impending conflict under general assumptions about aircraft dynamics. The decision-making logic that selects the appropriate maneuvers is encoded in a stochastic policy encapsulated as a neural network. The networks parameters are optimized to maximize a reward function. The reward function penalizes loss of separation with other aircraft while rewarding resolutions that result in minimum excursions from the nominal flight plan. This paper provides a description of the technique and presents preliminary simulation results

Node balanced steady states: Unifying and generalizing complex and detailed balanced steady states

We introduce a unifying and generalizing framework for complex and detailed balanced steady states in chemical reaction network theory. To this end, we generalize the graph commonly used to represent a reaction network. Specifically, we introduce a graph, called a reaction graph, that has one edge for each reaction but potentially multiple nodes for each complex. A special class of steady states, called node balanced steady states, is naturally associated with such a reaction graph. We show that complex and detailed balanced steady states are special cases of node balanced steady states by choosing appropriate reaction graphs. Further, we show that node balanced steady states have properties analogous to complex balanced steady states, such as uniqueness and asymptotic stability in each stoichiometric compatibility class. Moreover, we associate an integer, called the deficiency, to a reaction graph that gives the number of independent relations in the reaction rate constants that need to be satisfied for a positive node balanced steady state to exist. The set of reaction graphs (modulo isomorphism) is equipped with a partial order that has the complex balanced reaction graph as minimal element. We relate this order to the deficiency and to the set of reaction rate constants for which a positive node balanced steady state exists

Addition of flow reactions preserving multistationarity and bistability

We consider the question whether a chemical reaction network preserves the number and stability of its positive steady states upon inclusion of inflow and outflow reactions. Often a model of a reaction network is presented without inflows and outflows, while in fact some of the species might be degraded or leaked to the environment, or be synthesized or transported into the system. We provide a sufficient and easy-to-check criterion based on the stoichiometry of the reaction network alone and discuss examples from systems biology

Melissa officinalis and Passiflora caerulea infusion as physiological stress decreaser

Rivera, C (reprint author) Univ Talca, Fac Hlth Sci, Unit Histol & Embryol, Dept Basic Biomed Sci, Talca, ChileThe objective of this study was to determine the effect of a Melissa officinalis and Passiflora caerulea infusion on the severity of physiological chronic stress induced by movement restriction in CF-1 mice. 40 CF-1 male mice, six weeks of age, were divided into 4 groups (n = 10 for each group): (1) Group RS/MP received two treatments, induced stress through movement restriction and a infusion of Melissa officinalis and Passiflora caerulea in a dose of 200 mg/kg, (2) RS group with induced stress using movement restriction, (3) MP group, which received only a infusion, and (4) a CONTROL group that received no treatment. The severity of the stress was obtained by analysis of the physical parameters of body weight, thymus and spleen, and associated biomarkers with stress, corticosterone, and glucose. Animals that consumed Melissa officinalis and Passiflora caerulea infusion had lower plasma corticosterone levels (Student's t test, Welch, p = 0.05), which is the most important biomarker associated with physiological stress, demonstrating a phytotherapy effect

Independent Configurable Architecture for Reliable Operation of Unmanned Systems with Distributed Onboard Services

This paper presents the development of ICAROUS-2 (Independent Configurable Architecture for Reliable Operation of Unmanned Systems with Distributed Onboard Services), the second generation of a software architecture that integrates several algorithms as distributed onboard services to enable robust autonomous UAS applications. In particular, the ICAROUS architecture defines a framework to perform detect and avoid, geofencing, path monitoring, path planning, and autonomous decision making to ensure safety and mission progress. Most of the core algorithms implemented in ICAROUS are formally verified using an interactive theorem prover. These algorithms are composed together using a plan execution engine, whose operational semantics is formally specified. A description of the integrated architecture, services currently available, and flight test results highlighting the capability of ICAROUS are presented

Assessing the reliability and validity of agility testing in team sports: a systematic review

The aims of this systematic review were to: 1) examine the reliability of the reactive agility tests and, 2) analyse the discriminatory validity of the agility tests. A literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We explored PubMed, SPORTDiscus and Cochrane Plus databases looking for articles about agility in team sports. After filtering for article relevance, only 42 studies met the inclusion criteria; 37 of which assessed the reliability of agility tests and 22 assessing their validity. Reliability showed a high ICC in almost all studies (range 0.79-0.99) with the exception of two studies. In addition, other studies also assessed the reliability of decision time (ICC=0.95), movement time (ICC=0.92) and decision accuracy (ICC=0.74-0.93), all of which exhibited acceptable reliability. Furthermore, these data show high discriminatory validity, with higher performance players being faster than lower performance level players (mean = 6.4%, range = 2.1-25.3%), with a faster decision time (mean = 23.2%, range = 10.2-48.0%) with the exception of one study, and better decision accuracy (mean = 9.3%, range = 2.5-21.0%). Thus, it can be concluded that reactive agility tests show good reliability and discriminatory validity. However, most agility tests occur in simple contexts whereby only two possible responses are possible. Therefore, future research should consider creating more specific and complex environments which challenge the cognitive process of high-level athletes

La contratación pública de obras: situación actual y puntos de mejora

La construcción pública ha sido, es y será uno de los pilares fundamentales del sector construcción español, si bien la actual situación de crisis económica y la reducción de la inversión pública en nuevas infraestructuras ha generado un descenso de actividad hasta niveles similares a los años noventa. El retorno a índices de actividad más elevados no solo se conseguirá con la recuperación de la economía del país, sino que será necesario realizar ciertas mejoras en los procesos de licitación con objeto de conseguir una mayor funcionalidad y flexibilidad en la contratación pública de obras

Phylogeographic Triangulation: Using Predator-Prey-Parasite Interactions to Infer Population History from Partial Genetic Information

Phylogeographic studies, which infer population history and dispersal movements from intra-specific spatial genetic variation, require expensive and time-consuming analyses that are not always feasible, especially in the case of rare or endangered species. On the other hand, comparative phylogeography of species involved in close biotic interactions may show congruent patterns depending on the specificity of the relationship. Consequently, the phylogeography of a parasite that needs two hosts to complete its life cycle should reflect population history traits of both hosts. Population movements evidenced by the parasite’s phylogeography that are not reflected in the phylogeography of one of these hosts may thus be attributed to the other host. Using the wild rabbit (Oryctolagus cuniculus) and a parasitic tapeworm (Taenia pisiformis) as an example, we propose comparing the phylogeography of easily available organisms such as game species and their specific heteroxenous parasites to infer population movements of definitive host/predator species, independently of performing genetic analyses on the latter. This may be an interesting approach for indirectly studying the history of species whose phylogeography is difficult to analyse directly

Bibliotecas nacionales y robótica : el sistema de robots de la Biblioteca Valenciana

The management of the physical documentation continues being a challenge of many centers, especially in those that, as the national libraries, should negotiate enormous collections and to adapt uses and guidelines of work to buildings with a high historic-artistic value. Is the case of the Biblioteca Valenciana, the national library of the Valencian Community, that since the year 2000 counts on own headquarters in the Monastery of San Miguel de los Reyes, jewel of the Spanish and Valencian renaissance. The study describes the system of robots installed in said year, its characteristics, utilities and advantages, as well as the problematic one detected after four years of operation