A note on variable threshold concept lattices: Threshold-based operators are reducible to classical concept-forming operators

The present paper deals with formal concept analysis of data with fuzzy attributes. We clarify several points of a new approach of [S.Q. Fan, W.X. Zhang, Variable threshold concept lattice, Inf. Sci., accepted for publication] which is based on using thresholds in concept-forming operators. We show that the extent- and intent-forming operators from [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication] can be defined in terms of basic fuzzy set operations and the original operators as introduced and studied e.g. in [R. Belohlavek, Fuzzy Galois connections, Math. Logic Quarterly 45 (4) (1999) 497-504; R. Belohlavek, Concept lattices and order in fuzzy logic, Ann. Pure Appl. Logic 128 (2004) 277-298; S. Pollandt, Fuzzy Begriffe, Springer-Verlag, Berlin/Heidelberg, 1997]. As a consequence, main properties of the new operators from [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication], including the properties studied in [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication], can be obtained as consequences of the original operators from [R. Belohlavek, 1999; R. Belohlavek, 2004; S. Pollandt, 1997].     

Sup-t-norm and inf-residuum are a single type of relational equations

We show that the sup-t-norm and inf-residuum types of fuzzy relational equations, considered in the literature as two different types, are in fact two particular instances of a single, more general type of equations. We demonstrate that several pairs of corresponding results on the sup-t-norm and inf-residuum types of equations are simple consequences of single results regarding the more general type of equations. We also show that the new type of equations subsumes other types of equations such as equations with constraints on solutions, examples of which are fuzzy relational equations whose solutions are required to be crisp (ordinary) relations.     

Formal concept analysis with background knowledge: a case study in paleobiological taxonomy of belemnites

We present a case study in identification of taxa in paleobiological data. Our approach utilizes formal concept analysis and is based on conceiving a taxon as a group of individuals sharing a collection of attributes. In addition to the incidence relation between individuals and their attributes, the method uses expert background knowledge regarding importance of attributes which helps to filter out correctly formed but paleobiologically irrelevant taxa. We present results of experiments carried out with belemnites—a group of extinct cephalopods which seems particularly suitable for such a purpose. We demonstrate that the methods are capable of revealing taxa and relationships among them that are relevant from a paleobiological point of view.     

Hybrid semiconductor electrodes for light-driven photoelectrochemical switches

Hybrid (n-/p-type) semiconductor electrodes represent a viable strategy for fabrication of wavelength-controlled optoelectronic switches. Four hybrid electrodes (BiVO₄/Co₃O₄, BiVO₄/CuO, TiO₂/Co₃O₄, TiO₂/CuO) were prepared in the form of random assemblies of nanocrystalline powders on ITO-glass and the wavelength dependence of their photocurrent response was investigated. The former three electrodes exhibited wavelength-controlled switching of photocurrent direction, whereas the latter one showed exclusively cathodic photocurrents. The prerequisite for the switching effect is that the potentials of the valence and conduction band edges of an n-type component are more positive than those of a p-type one. Further key parameters influencing the photocurrent response are the applied potential and the presence of electron and hole scavengers.     

Enhanced visible light photocurrent generation at surface-modified TiO2 nanotubes

Photoelectrodes consisting of TiO₂ nanotube layers with different thicknesses (0.5 μm, 1.7 μm, 3 μm, 6 μm, 9 μm, and 18 μm) were prepared by anodization of titanium substrates and subsequent surface modification by a heat treatment at 400 °C in the presence of urea pyrolysis products. In contrast to unmodified TiO₂ nanotubes, the modified photoelectrodes exhibit photocurrents under visible light irradiation down to 750 nm. Photocurrent transients indicate enhanced recombination unless a suitable hole-scavenger, like iodide, is present since the photogenerated holes do not oxidize water efficiently. In the visible light the photoconversion efficiency increases significantly with nanotube length. The maximum incident photon-to-current efficiency (IPCE) was observed for tubes with the length of 6-9 μm (IPCE ∼4.5% and 1.4% at 450 nm and 550 nm, respectively) and the photocurrent enhancement with increasing tube length is found to be stronger at longer irradiations wavelengths.     

基于Motorola DSP5680x系列的无传感器开关磁阻电机控制(上)

引言开关磁阻(SR)电机正以其可变速驱动而越来越受欢迎，它具有结构简单、成本低、无磁体和转子线圈的特点，在较大的速度范围内都具有很高的性能，并且它的功率放大器具有容错功能。SR驱动的缺点是需要知道转子位置信息，以便给出每相适合的开关控制状态。用无传感器控制技术可以避免使用位置传感器。这些技术通过测算电机电压和电流来确定转子在电机运行时的位置。现在已经开发了多种无传感器算法，本文介绍了带有电机控制专用外设的高性能控制器，读者可以利用它们为工业、仪器和自动化应用设计可靠的无传感器SR驱动。Motorola DSP中…     

Integrating Differentiated Services with ATM

IP in the edge and ATM in the core are commonplace in today's internetworks. The IETF has proposed a new Quality of Service (QoS) mechanism namely Differentiated Services (DiffServ) for IP networks. On the other hand, QoS is an inherent feature in ATM. It is imperative that IP and ATM QoS interoperate efficiently to provide an end-to-end service guarantee. DiffServ provides a class of service named Assured Forwarding (AF) that does not exactly correlate to any of the service categories offered by ATM. AF is targeted towards a range of applications, such as real-time (rt) that do not require a constant bit rate service provided by Expedited Forwarding, and other non-real-time (nrt) applications that expect a service better than best effort. In this paper we propose the mapping of AF to the Variable Bit Rate (VBR) service category in ATM. VBR is suitable because it is available in the form of rt-VBR and nrt-VBR and could be translated appropriately based on the applications. The mapping is implemented and verified using the LBNL Network Simulator. The results of the experiments show that VBR is a better match for AF than any other service category in ATM.     

Prediction of Power Consumption in a Mechanically Agitated Gassed Reactor in Viscous Batches

Volumetric mass transfer coefficient, power input, and gas holdup are key parameters in the design of mechanically agitated gas‐liquid contactors. Although the majority of industrial batches are of higher viscosity, reliable transport characteristics correlations for viscous batches are lacking in literature. These correlations are often based on the power input as the scale of energy dissipation. In order to develop reliable power input correlations, its measurements were carried out in a pilot‐plant vessel using multiple impellers of various types and diameters. Power input correlation shapes providing the best match with the comprehensive database are also expected to predict most precisely the impeller power in industrial‐scale vessels.     

Systems,uncertainty, and information: A legacy of George J. Klir

This paper tracks scientific work and contributions of George J. Klir (1932–2016), one of the major figures in systems movement and the founder of this journal.