SELF-SIMILARITY TECHNIQUES FOR CHAOTIC ATTRACTORS WITH MANY SCROLLS USING STEP SERIES SWITCHING

Highly applied in machining, image compressing, network traffic prediction, biological dynamics, nerve dendrite pattern and so on, self-similarity dynamic represents a part of fractal processes where an object is reproduced exactly or approximately exact to a part of itself. These reproduction processes are also very important and captivating in chaos theory. They occur naturally in our environment in the form of growth spirals, romanesco broccoli, trees and so on. Seeking alternative ways to reproduce self-similarity dynamics has called the attention of many authors working in chaos theory since the range of applications is quite wide. In this paper, three combined notions, namely the step series switching process, the Julia’s technique and the fractal-fractional dynamic are used to create various forms of self-similarity dynamics in chaotic systems of attractors, initially with two, five and seven scrolls. In each case, the solvability of the model is addressed via numerical techniques and related graphical simulations are provided. It appears that the initial systems are able to trigger a self-similarity process that generates the exact or approximately exact copy of itself or part of itself. Moreover, the dynamics of the copies are impacted by some model’s parameters involved in the process. Using mathematical concepts to re-create features that usually occur in a natural way proves to be a prowess as related applications are many for engineers.

Conceptualizing the supplier switching process: an example from public procurement

Purpose This paper aims to develop a framework for switching a service supplier in a supply network. Design/methodology/approach The study builds on existing literature in the field of purchasing and supply management, public procurement (PP) and the Industrial Marketing and Purchasing approach, as well as on an illustrative example case, from the PP context, of a supplier switch in a service delivery process. Findings During a switching process, the buyer must simultaneously manage the ending of a relationship with the incumbent supplier and the beginning of a relationship with a new supplier. Collaboration with the focal suppliers to develop a service process with standardized components prevents disruptions in the service processes and reduces the impact of the switch on the wider network. Research limitations/implications The conceptualization suggested in this paper needs to be further explored in different empirical contexts to assess its practical adequacy. Practical implications Practitioners responsible for service procurement can use the findings to develop collaboration with suppliers, both when it comes to service process development and to the switching process. Furthermore, the authors highlight the importance of ending competencies and the development of an exit plan to conduct a “beautiful exit.” Originality/value The paper integrates relationship initiation and ending studies, as well as procurement process models to develop a refined switching process framework. Many PPs rely on short-term relationships due to the legal obligation to frequently invite suppliers to tender, thus understanding the supplier switching process is important both for private and public sector actors.

Performance evaluation of GaN and Si based driver circuits for a SiC MOSFET power switch

<p>Silicon Carbide (SiC), new power switches (PSW) require new driver circuits which can take advantage of their new capabilities. In this paper a novel Gallium Nitride (GaN) based gate driver is proposed as a solution to control SiC power switches. The proposed driver is implemented and is performance compared with its silicon (Si) counterparts on a hard switching environment. A thorough evaluation of the energy involved in the switching process is presented showing that the GaN based circuit exhibits similar output losses but reduces the control power needed to operate at a specified frequency.</p>

Homogeneous versus Inhomogeneous Polarization Switching in PZT Thin Films: Impact of the Structural Quality and Correlation to the Negative Capacitance Effect

Polarization switching in ferroelectric films is exploited in many applications, such as non-volatile memories and negative capacitance field affect transistors. This can be inhomogeneous or homogeneous, depending on if ferroelectric domains are forming or not during the switching process. The relation between the polarization switching, the structural quality of the films and the negative capacitance was not studied in depth. Here, Pb(Zr0.2Ti0.8)O3 (PZT) layers were deposited by pulse laser deposition (PLD) and sol-gel (SG) on single crystal SrTiO3 (STO) and Si substrates, respectively. The structural quality was analyzed by X-ray diffraction and transmission electron microscopy, while the electric properties were investigated by performing hysteresis, dynamic dielectric measurements, and piezo-electric force microscopy analysis. It was found that the PZT layers grown by PLD on SRO/STO substrates are epitaxial while the layers deposited by SG on Pt/Si are polycrystalline. The polarization value decreases as the structure changes from epitaxial to polycrystalline, as well as the magnitude of the leakage current and of the differential negative capacitance, while the switching changes from homogeneous to inhomogeneous. The results are explained by the compensation rate of the depolarization field during the switching process, which is much faster in epitaxial films than in polycrystalline ones.

Miller Plateau Corrected with Displacement Currents and Its Use in Analyzing the Switching Process and Switching Loss

This paper reveals the relationship between the Miller plateau voltage and the displacement currents through the gate–drain capacitance (CGD) and the drain–source capacitance (CDS) in the switching process of a power transistor. The corrected turn-on Miller plateau voltage and turn-off Miller plateau voltage are different even with a constant current load. Using the proposed new Miller plateau, the turn-on and turn-off sequences can be more accurately analyzed, and the switching power loss can be more accurately predicted accordingly. Switching loss models based on the new Miller plateau have also been proposed. The experimental test result of the power MOSFET (NCE2030K) verified the relationship between the Miller plateau voltage and the displacement currents through CGD and CDS. A carefully designed verification test bench featuring a power MOSFET written in Verilog-A proved the prediction accuracy of the switching waveform and switching loss with the new proposed Miller plateau. The average relative error of the loss model using the new plateau is reduced to 1/2∼1/4 of the average relative error of the loss model using the old plateau; the proposed loss model using the new plateau, which also takes the gate current’s variation into account, further reduces the error to around 5%.

Uptake of Trastuzumab Biosimilars for the Treatment of HER2-Positive Breast Cancer: A Real-World Experience from a Cancer Center

Background: The introduction of trastuzumab biosimilars in clinical practice plays an important role in promoting the sustainability of healthcare systems. By contrast, the switching process can be challenging to the clinics. This survey describes the switching process at a National Cancer Institute over a period of 2 years. Methods: Data regarding all trastuzumab-based regimens for breast cancer (BC) from 1 January 2019 and 31 December 2020 were extracted from both adverse drug reactions (ADRs) reporting systems and electronic systems involved in inventory management, prescribing, dispensing, and administration. Both patients under monotherapy and combination treatment regimens were included. There were no exclusion criteria. Results and Conclusions: Overall 354 patients received at least one trastuzumab-based regimen for a total of 493 lines of treatment and 5769 administrations. Biosimilar were used in 34.3% of trastuzumab-based treatments. No differences between biosimilars and reference drug have been observed in terms of ADRs. The effective cost-saving of the first 2 years is greater than EUR 800,000 and it is estimated to increase over time.