Crack patterns in thin layers under temperature loading Part II: Cyclic loading

The paper presents an analysis of cracking and delamination of an elastic plate bonded to a rigid substrate. The plate is subjected to a cyclic temperature loading. The bond between the plate and the substrate is simulated using rigid-frictional and rigid-cohesive-frictional interface models. The states of adaptation or incremental failure are distinguished in the case of the softening interfacial law. The proposed modelling is validated to predict fragmentation of a concrete pavement subjected to temperature loading. The obtained results can serve as reference solutions for numerical calculations of more complex cases.     

Alternative Local Melting-Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non-equilibrium kinetic by-products resulting from the localized alternative, fast, high-temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu-CuO-Cu₂O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano-laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO-ethanol and Cu-ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic-augmented Cu³⁺ by-product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab-initio calculations and experimental observations.     

Vector-Field-Orientation Tracking Control for a Mobile Vehicle Disturbed by the Skid-Slip Phenomena

The paper is devoted to the trajectory tracking control task for a differentially-driven vehicle moving on a plane surface under conditions of the persistent skid-slip phenomena. The Vector Field(s) Orientation (VFO) control strategy, presented originally for undisturbed case in Micha?ek and Koz?owski (IEEE Trans Control Syst Technol 18(1):45–65, 2010), has been reformulated here to the new disturbed motion conditions. The extension of the VFO strategy relies on introduction of the nonlinear skid-slip influence compensator in the feed-forward loop, which in practical implementation involves the real-time estimation of the skid-slip velocities and their time-derivatives. The approach considers the skid-slip effects solely on the kinematic level avoiding the need of modeling a complicated phenomenon of the wheels-ground interaction. Theoretical analysis shows the asymptotic tracking ability for the position trajectory with boundedness of the orientation error. Experimental results included in the paper reveal substantial tracking quality improvement resulting from the utilization of the proposed skid-slip influence compensator.     

The notion of diversity in graphical entity summarisation on semantic knowledge graphs

Given an entity represented by a single node q in semantic knowledge graph D, the Graphical Entity Summarisation problem (GES) consists in selecting out of D a very small surrounding graph S that constitutes a generic summary of the information concerning the entity q with given limit on size of S. This article concerns the role of diversity in this quite novel problem. It gives an overview of the diversity concept in information retrieval, and proposes how to adapt it to GES. A measure of diversity for GES, called ALC, is defined and two algorithms presented, baseline, diversity-oblivious PRECIS and diversity-aware DIVERSUM. A reported experiment shows that DIVERSUM actually achieves higher values of the ALC diversity measure than PRECIS. Next, an objective evaluation experiment demonstrates that diversity-aware algorithm is superior to the diversity-oblivious one in terms of fact selection. More precisely, DIVERSUM clearly achieves higher recall than PRECIS on ground truth reference entity summaries extracted from Wikipedia. We also report another intrinsic experiment, in which the output of diversity-aware algorithm is significantly preferred by human expert evaluators. Importantly, the user feedback clearly indicates that the notion of diversity is the key reason for the preference. In addition, the experiment is repeated twice on an anonymous sample of broad population of Internet users by means of a crowd-sourcing platform, that further confirms the results mentioned above.     

Towards large-scale multimedia retrieval enriched by knowledge about human interpretation

Recent Large-Scale Multimedia Retrieval (LSMR) methods seem to heavily rely on analysing a large amount of data using high-performance machines. This paper aims to warn this research trend. We advocate that the above methods are useful only for recognising certain primitive meanings, knowledge about human interpretation is necessary to derive high-level meanings from primitive ones. We emphasise this by conducting a retrospective survey on machine-based methods which build classifiers based on features, and human-based methods which exploit user annotation and interaction. Our survey reveals that due to prioritising the generality and scalability for large-scale data, knowledge about human interpretation is left out by recent methods, while it was fully used in classical methods. Thus, we defend the importance of human-machine cooperation which incorporates the above knowledge into LSMR. In particular, we define its three future directions (cognition-based, ontology-based and adaptive learning) depending on types of knowledge, and suggest to explore each direction by considering its relation to the others.     

Application of the consensus method in a multiagent financial decision support system

Financial decisions are supported by different methods, based mainly on statistics, mathematics, behaviorism, artificial intelligence or experts’ opinion sentiment analysis. The main problem is that under conditions of risk and uncertainty predicting financial markets can be very difficult. This paper presents an approach to investment strategy design for a multiagent system which supports investment decisions on the stock market. Individual components and functionalities of the multiagent financial decision support system method have been briefly described. On the basis of decisions generated by agents, the Supervisor Agent uses a consensus method to generate a satisfactory rate of return and reduce the level of risk associated with investing in a financial instrument. Verification of the effectiveness of the strategy has been conducted using investments on the Warsaw Stock Exchange.     

On the mass and momentum transport in the Navier–Stokes slip layer

The Navier–Stokes slip boundary conditions are considered as conditions following from the mass and momentum balances within a thin, shell-like moving boundary layer. A problem of consistency between different models, that describes the internal and external friction in a viscous fluid, is stated within the framework of a proper form of the layer momentum balance. Appropriate constitutive equations for friction forces are formulated. The common features of the Navier, Stokes, Reynolds, and Maxwell concepts of a boundary slip layer are revalorized and discussed. Different mobility mechanisms connected with the transpiration phenomena, important for flows in micro- and nanochannels, are classified as a part of equations for the external friction.