Parametric analysis of the stability of a bicycle taking into account geometrical, mass and compliance properties

Some studies of bicycle dynamics have applied the Whipple Carvallo bicycle model (WCBM) for the stability analysis. The WCBM is limited, since structural elements are assumed to be rigid bodies. In this paper, the WCBM is extended to include the front assembly lateral compliance, and analysis focuses on the study of the open loop stability of a benchmark bicycle. Experimental tests to identify fork and wheel properties are performed, this data is used in the stability analysis for ranking the influence of design parameters. Indexes from the eigenvalues analysis are applied in a full factorial approach. The results show that introducing front assembly compliance generates a wobble mode with little effect on self-stability. The forward displacement of the centre of mass of the rear frame and the increment in trail lead to large increments in the self-stability, whereas increments in front wheel radius and wheelbase reduce stability

Very well covered graphs

AbstractA graph is well-covered if it has no isolated vertices and all the maximal stable (independent) sets have the same cardinality. If furthermore this cardinality is equal to 12n, where n is the order of the graph, the graph is called ‘very well covered’. The class of very well-covered graphs contains in particular the bipartite well-covered graphs studied by Ravindra. In this article, we characterize the very well covered-graphs and give some of their properties

Development and testing of an MPC attitude controller for an ROV

openMarine exploration utilizing Remotely Operated Vehicles (ROVs) has become integral to understanding the oceanic environment. Coordinating multiple vehicles concurrently is a critical aspect of enhancing exploration efficiency. This thesis focuses on the development and testing of a Model Predictive Control (MPC) combined controller for an Autonomous Underwater Vehicle (AUV) and an Uncrewed Surface Vehicle (USV) ROV.\\ Recognizing the importance of coordinated marine exploration, the research investigates the implementation of an MPC algorithm to control both AUVs and USVs simultaneously. The study is conducted in simulated environments to assess the controller's performance under varying conditions.\\ The development process involves designing a versatile MPC controller capable of effectively coordinating the movements of AUVs and USVs. The goal is to optimize their trajectories and maintain synchronized exploration patterns and a stable optical based connection. The unique dynamics of each vehicle type are considered to ensure adaptability and robust performance in the challenging underwater environment.\\ This research contributes to the advancement of marine exploration by addressing the challenges of coordinating multiple vehicles. The MPC combined controller offers a possible solution for optimizing exploration missions, providing a foundation for further developments in autonomous marine systems.Marine exploration utilizing Remotely Operated Vehicles (ROVs) has become integral to understanding the oceanic environment. Coordinating multiple vehicles concurrently is a critical aspect of enhancing exploration efficiency. This thesis focuses on the development and testing of a Model Predictive Control (MPC) combined controller for an Autonomous Underwater Vehicle (AUV) and an Uncrewed Surface Vehicle (USV) ROV.\\ Recognizing the importance of coordinated marine exploration, the research investigates the implementation of an MPC algorithm to control both AUVs and USVs simultaneously. The study is conducted in simulated environments to assess the controller's performance under varying conditions.\\ The development process involves designing a versatile MPC controller capable of effectively coordinating the movements of AUVs and USVs. The goal is to optimize their trajectories and maintain synchronized exploration patterns and a stable optical based connection. The unique dynamics of each vehicle type are considered to ensure adaptability and robust performance in the challenging underwater environment.\\ This research contributes to the advancement of marine exploration by addressing the challenges of coordinating multiple vehicles. The MPC combined controller offers a possible solution for optimizing exploration missions, providing a foundation for further developments in autonomous marine systems

FROM IRREDUNDANCE TO ANNIHILATION: A BRIEF OVERVIEW OF SOME DOMINATION PARAMETERS OF GRAPHS

Durante los últimos treinta años, el concepto de dominación en grafos ha levantado un interés impresionante. Una bibliografía reciente sobre el tópico contiene más de 1200 referencias y el número de definiciones nuevas está creciendo continuamente. En vez de intentar dar un catálogo de todas ellas, examinamos las nociones más clásicas e importantes (tales como dominación independiente, dominación irredundante, k-cubrimientos, conjuntos k-dominantes, conjuntos Vecindad Perfecta, ...) y algunos de los resultados más significativos.   PALABRAS CLAVES: Teoría de grafos, Dominación.   ABSTRACT During the last thirty years, the concept of domination in graphs has generated an impressive interest. A recent bibliography on the subject contains more than 1200 references and the number of new definitions is continually increasing. Rather than trying to give a catalogue of all of them, we survey the most classical and important notions (as independent domination, irredundant domination, k-coverings, k-dominating sets, Perfect Neighborhood sets, ...) and some of the most significant results.   KEY WORDS: Graph theory, Domination

On the Behaviour of Singular Semigroups in Intermediate and Interpolation Spaces and Its Applications to Maximal Regularity for Degenerate Integro-Differential Evolution Equations

For those semigroups, which may have power type singularities and whose generators are abstract multivalued linear operators, we characterize the behaviour with respect to a certain set of intermediate and interpolation spaces. The obtained results are then applied to provide maximal time regularity for the solutions to a wide class of degenerate integro- and non-integro-differential evolution equations in Banach spaces

On the bipartite independence number of a balanced bipartite graph

AbstractThe bipartite independence number αBIP of a bipartite graph G is the maximum order of a balanced independent set of G. Let δ be the minimum degree of the graph. When G itself is balanced, we establish some relations between αBIP and the size or the connectivity of G. We also prove that the condition αBIP⩽δ(resp.αBIP⩽δ−1) implies that G is hamiltonian (resp. Hamilton-biconnected), thus improving a result of Fraisse

Biocontrol Ability and Action Mechanism of Starmerella bacillaris (Synonym Candida zemplinina) Isolated from Wine Musts against Gray Mold Disease Agent Botrytis cinerea on Grape and Their Effects on Alcoholic Fermentation

Gray mold is one of the most important diseases of grapevine in temperate climates. This plant pathogen affects plant growth and reduces wine quality. The use of yeasts as biocontrol agents to apply in the vineyard have been investigated in recent years as an alternative to agrochemicals. In this work, fermenting musts obtained from overripe grape berries, therefore more susceptible to infection by fungal pathogens such as Botrytis cinerea, were considered for the selection of yeasts carrying antifungal activity. Thirty-six isolates were identified as Starmerella bacillaris, a species recently proven to be of enological interest. Among them 14 different strains were studied and antifungal activity against B. cinerea was demonstrated, for the first time, to be present in S. bacillaris species. The production of volatile organic compounds (VOCs), tested in vitro, was found to be the main responsible of S. bacillaris antifungal effects. All the strains were able to reduce B. cinerea decay on wounded grape berries artificially inoculated with gray mold. The colonization level of wound was very high reaching, after 5 days, a concentration of 10(6) cells per ml of grape juice obtained after berry crushing. At this cell concentration S. bacillaris strains were used to ferment synthetic and natural musts. The sequential yeast inoculation, performed by adding S. cerevisiae 48 h after S. bacillaris, was needed to complete sugar consumption and determined a significant increase in glicerol content and a reduction of ethanol and acetic acid concentrations. The high wound colonization ability, found in this work, together with the propensity to colonize grape berry and the interesting enological traits possessed by the selected S. bacillaris strains allow the use of this yeast as biocontrol agent on vine and grape berries with possible positive effects on must fermentation, although the presence of S. cerevisiae is needed to complete the fermentation process. This work introduces new possibilities in wine yeast selection programs in order to identify innovative wine yeasts that are simultaneously antifungal agents in vineyards and alternative wine starters for grape must fermentation and open new perspective to a more integrated strategy for increasing wine quality