Logical derivation search with assumption traceability

In this paper authors research the problem of traceability of assumptions in logical derivation. The essence of this task is to trace which assumptions from the available knowledge base of assumptions are necessary to derive a certain conclusion. The paper presents a new derivation procedure for propositional logic, which ensures traceability feature. For the derivable conclusion formula derivation procedure also returns the smallest set of assumptions those are enough to get derivation of the conclusion formula. Verification of the procedure were performed using authors implementation.

Vegetation Survival in Green Roofs without Irrigation

The implementation of green roofs as sustainable urban drainage systems provides benefits for stormwater control and the environment and is more and more encouraged. A model for the estimation of the probability of vegetation survival without irrigation is proposed. The model, developed through a probabilistic analytical derivation procedure, can also consider the effects of chained rainfall events, without the need of continuous simulation of hydrological processes. The model equations can be useful in the design of green roofs, allowing to determine the growing medium thickness in terms of an assumed risk of vegetation withering in dry periods. The proposed model is also able to identify the optimal thickness of the growing medium, over which the survival performances can be increased only with irrigation. Model performances were tested by the application to two case studies in Italy. Comparison between the probabilities and the cumulative frequencies from a continuous simulation of water content in the growing medium shows a good agreement and provide a first confirmation of reliability.

The alternative derivation procedure of equations of the law of the junction for the study of the p-n junction theory

The methodology that increases the student interest and provides modern knowledge to the study of the p-n junction theory has been proposed. It is based on two methods: increasing the interest of students using a new approach in derivation of equations of the law of the junction that allows obtaining more comprehensive knowledge about the operation of the p-n junctions and engaging students using the storytelling technique. The reaction of students to the lecture, obtained statistics on the student activity and the results of the student survey show that the proposed methodology allows increasing the student engagement in the p-n junction theory lectures.

Line-finite-element implementation for driven steel H-piles in layered sands considering post-driving residual stresses

Driven Steel H-piles are commonly used in the deep foundation of being cost-effective and easy in workmanship. The post-driving residual stresses acting on the pile could be large when being driven in cohesionless sands, significantly affecting its compressive strength. Current design methods, mostly based on the empirical assumptions of using safety factors, are unable to consider the post-driving residual stresses on piles accurately and usually very conservative in practical applications. Such consideration is further complicated when the pile is embedded in layered sands. Moreover, the soil-structure interaction (SSI) between pile and ground medium is usually complicated in the analysis and should be appropriately considered in a successful design. This paper proposes a line-finite-element implementation method, based on the Euler-Bernoulli pile element formulations, for robustly and efficiently analyzing the driven steel H-piles in layered sands with explicitly modelling the SSI. The effects resulting from the post-driving residual stresses are considered in the total potential energy equation for generating the secant relations. The derivation procedure is elaborated with details. Consequentially, verification examples are given for validating the accuracy of the proposed method. This work would be helpful for improving the numerical efficiency and accuracy for designing the steel H-piles in layered sands.

Determining the Effective Range of Radar Horizontal Reflectivity-Rainfall Intensity Relationship

This study evaluated the applicability of the reflectivity-rainfall (Z-R) relationship using horizontal reflectivity. We reviewed the derivation procedure of the Z-R relationship and transformed the equation to estimate the parameters of drop size distribution from the observational data. The parameters of drop size distribution were estimated for the paired data of horizontal reflectivity and rainfall rate observed at the Gwanaksan and Biseulsan radar stations by applying this equation. Subsequently, the representative values of these estimated parameters were used to derive the Z-R relationship. Finally, we evaluated the performance of the Z-R relationship for representing the observed horizontal reflectivity-rainfall intensity data. It was observed that the difference between the theoretical estimation and the observed data increases as the radar reflectivity decreases. Moreover, the results confirmed that the Z-R relationship based on the assumption of exponentially distributed drop size distribution may not be applicable for all reflectivity ranges.

A Comparison between Elastic and Viscoelastic Asymmetric Dynamics of Elastically Supported AFG Beams

This investigation compares the dynamic simulation results of perfect, elastically-supported, axially-functionally-graded (AFG) beams between viscoelastic and elastic models. When modeling and simulating the dynamics of AFG beams, the elastic model is commonly assumed so as to simplify calculations. This investigation shows how the dynamics varies if viscosity is present. The nonlinear continuous/discretized, axial/transverse motion derivation procedure is explained briefly based on Hamilton’s principle for energy/energy-loss, Kelvin–Voigt viscosity, elastic foundation assumption, and exponential functions for material and geometric variations along the axial axis. A comparison between elastic and Kelvin–Voigt viscoelastic AFG beams on an elastic foundation shows that the viscosity influences the asymmetric dynamics of AFG beams; the viscosity effects become more dominant for larger motion amplitudes, for example.

A Topology Synthetization Method for Single-Phase, Full-Bridge, Transformerless Inverter with Leakage Current Suppression Part I

Single-phase full-bridge transformerless topologies, such as the H5, H6, or the highly efficient and reliable inverter concept (HERIC) topologies, are commonly used for leakage current suppression for photovoltaic (PV) applications. The main derivation methodology of full-bridge topologies has been used based on both a DC-based decoupling model and an AC-based decoupling model. However, this methodology is not suited to the search for all possible topologies, and cannot verify whether they are inclusive. Part I of this paper will propose a new topology derivation methodology based on unipolar sinusoidal pulse width modulation (USPWM) to search all possible full-bridge topologies for leakage current suppression. First of all, a unified circuit model is proposed, instead of the DC- and AC-based models. Secondly, a mathematic method called the MN principle is then proposed to search for all possible topologies, and a derivation procedure is provided. It was verified that all existing topologies could be found using the proposed method; furthermore, seven new topologies were derived. The proposed topology derivation methodology is extended to search topologies under Double-Frequency USPWM (DFUSPWM). Twenty topologies under USPWM and four topologies under DFUSPWM have been derived.

Extension of the Measurable Wavelength Range for a Near-Infrared Spectrometer Using a Plasmonic Au Grating on a Si Substrate

In this paper, we proposed near-infrared spectroscopy based on a Si photodetector equipped with a gold grating and extended the measurable wavelength range to cover 1200–1600 nm by improving a spectrum derivation procedure. In the spectrum derivation, photocurrent data during alteration of the incidence angle of the measured light were converted using a responsivity matrix R, which determines the spectroscopic characteristics of the photodetector device. A generalized inverse matrix of R was used to obtain the spectrum and to fit a situation where multiple surface plasmon resonance (SPR) peaks appeared in the scanning range. When light composed of two wavelengths, 1250 nm and 1450 nm, was irradiated, the two wavelengths were distinctively discriminated using the improved method.

A critical note on the IAGA-endorsed Polar Cap (PC) indices: excessive excursions in the real-time index values

The Polar Cap (PC) indices were approved by the International Association for Geomagnetism and Aeronomy (IAGA) in 2013 and made available at the web portal http://pcindex.org holding prompt (real-time) as well as archival index values. The present note provides the first reported examination of the validity of the IAGA-endorsed method to generate real-time PC index values. It is demonstrated that features of the derivation procedure defined by Janzhura and Troshichev (2011) may cause considerable excursions in the real-time PC index values compared to the final index values. In examples based on occasional downloads of index values, the differences between real-time and final values of PC indices were found to exceed 3 mV m−1, which is a magnitude level that may indicate (or hide) strong magnetic storm activity. Keywords. Magnetospheric physics (solar wind–magnetosphere interactions; polar cap phenomena) – ionosphere (modelling and forecasting)