scholarly journals Upgrading Behavioral Models for the Design of Digital Predistorters

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5350
Author(s):  
Carlos Crespo-Cadenas ◽  
María José Madero-Ayora ◽  
Juan A. Becerra

This work presents a strategy to upgrade models for power amplifier (PA) behavioral modeling and digital predistortion (DPD). These incomplete structures are the consequence of nonlinear order and memory depth model truncation with the purpose of reducing the demand of the limited computational resources available in standard processors. On the other hand, the alternative use of model structures pruned a priori does not guarantee that every significant term is included. To improve the limited performance of an incomplete model, a general procedure to augment its structure by incorporating significant terms is demonstrated. The sparse nature of the problem allows a successive search incorporating additional terms with higher nonlinear order and memory depth. This approach is investigated in the modeling and linearization of a commercial class AB PA operating at a compression point of about 6 dB, and a class J PA operating near saturation. Results highlight the capabilities of this upgrading procedure in the improvement of linearization capabilities of DPDs.

Author(s):  
Davorin Cimermančič ◽  
Janez Kušar ◽  
Tomaž Berlec

AbstractChanging a traditional company into a lean one is a very complex and time-consuming process that needs to be addressed in an appropriate way, otherwise the project of introduction of leanness into a company may fail on the one hand and even have a negative impact on business operations of the company on the other. When introducing a change, a step-by-step procedure leading to a progress may be of great help. The paper outlines a general procedure of leanness, an important part of which is a lean agent. A portfolio analysis is also used as a measure of leanness or as an indicator of the desired direction. The applied working methods were mainly active workshops and interviews with employees. The procedure has been tested on an example of a Slovene company; first, the existing situation is outlined, then the leanness steps taken according to the procedure and the final result after the first transition of the procedure.


2021 ◽  
Vol 26 (3) ◽  
pp. 1-17
Author(s):  
Urmimala Roy ◽  
Tanmoy Pramanik ◽  
Subhendu Roy ◽  
Avhishek Chatterjee ◽  
Leonard F. Register ◽  
...  

We propose a methodology to perform process variation-aware device and circuit design using fully physics-based simulations within limited computational resources, without developing a compact model. Machine learning (ML), specifically a support vector regression (SVR) model, has been used. The SVR model has been trained using a dataset of devices simulated a priori, and the accuracy of prediction by the trained SVR model has been demonstrated. To produce a switching time distribution from the trained ML model, we only had to generate the dataset to train and validate the model, which needed ∼500 hours of computation. On the other hand, if 10 6 samples were to be simulated using the same computation resources to generate a switching time distribution from micromagnetic simulations, it would have taken ∼250 days. Spin-transfer-torque random access memory (STTRAM) has been used to demonstrate the method. However, different physical systems may be considered, different ML models can be used for different physical systems and/or different device parameter sets, and similar ends could be achieved by training the ML model using measured device data.


Open Theology ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 430-450
Author(s):  
Kristóf Oltvai

Abstract Karl Barth’s and Jean-Luc Marion’s theories of revelation, though prominent and popular, are often criticized by both theologians and philosophers for effacing the human subject’s epistemic integrity. I argue here that, in fact, both Barth and Marion appeal to revelation in an attempt to respond to a tendency within philosophy to coerce thought. Philosophy, when it claims to be able to access a universal, absolute truth within history, degenerates into ideology. By making conceptually possible some ‚evental’ phenomena that always evade a priori epistemic conditions, Barth’s and Marion’s theories of revelation relativize all philosophical knowledge, rendering any ideological claim to absolute truth impossible. The difference between their two theories, then, lies in how they understand the relationship between philosophy and theology. For Barth, philosophy’s attempts to make itself absolute is a produce of sinful human vanity; its corrective is thus an authentic revealed theology, which Barth articulates in Christian, dogmatic terms. Marion, on the other hand, equipped with Heidegger’s critique of ontotheology, highlights one specific kind of philosophizing—metaphysics—as generative of ideology. To counter metaphysics, Marion draws heavily on Barth’s account of revelation but secularizes it, reinterpreting the ‚event’ as the saturated phenomenon. Revelation’s unpredictability is thus preserved within Marion’s philosophy, but is no longer restricted to the appearing of God. Both understandings of revelation achieve the same epistemological result, however. Reality can never be rendered transparent to thought; within history, all truth is provisional. A concept of revelation drawn originally from Christian theology thus, counterintuitively, is what secures philosophy’s right to challenge and critique the pre-given, a hermeneutic freedom I suggest is the meaning of sola scriptura.


2014 ◽  
Vol 687-691 ◽  
pp. 4060-4063
Author(s):  
Lu Sun ◽  
Long Long Xue ◽  
Jia Li Wang ◽  
Chun Yang Zhou

Memory effect of power amplifier (PA) due to broadband signals which adopt new modulation technique is becoming obvious, and worsening the linearity of PA. Behavioral modeling for RF (Radio Frequency) power amplifier is indispensable to design digital pre-distortion system by which we can promote the efficiency of PA. According to the simulation data in the software of ADS (Advanced Design System), behavioral models of MRF21085 amplifier can be established by MATLAB. Comparison of memory polynomial model and ADS simulation of MRF21085 amplifier demonstrate memory polynomial model can represent the electric characteristic of it exactly.


2020 ◽  
Vol 28 (3) ◽  
pp. 449-463 ◽  
Author(s):  
Natalia P. Bondarenko ◽  
Chung-Tsun Shieh

AbstractIn this paper, partial inverse problems for the quadratic pencil of Sturm–Liouville operators on a graph with a loop are studied. These problems consist in recovering the pencil coefficients on one edge of the graph (a boundary edge or the loop) from spectral characteristics, while the coefficients on the other edges are known a priori. We obtain uniqueness theorems and constructive solutions for partial inverse problems.


2013 ◽  
Vol 8 (1) ◽  
pp. 42-54
Author(s):  
Camille Carbonnaux

Since the 1990s, European judicial and normative institutions have paid particular attention to the competitive practices of public undertakings. Consequently, their regime is governed by a significant number of rules pursuing objectives appearing, a priori, contradictory. In fact, public undertakings may experience difficulties in their management. In this context, an approach of public competition law through the prism of fair competition can be very useful. Regarding the uniformity of its judgment, fair competition appears as an objective capable of coordinating rules and overcoming their contradictions. It thereby offers a global and coherent reading plan of all the legal translations of the European competitive order being of some practical importance. In illuminating the common features of the different legal aspects of competition, we can easily switch from one to the other. It therefore makes the European approach to competition more accessible and understandable. Furthermore, and most importantly, it leads to identifying legal opportunities and threats in a cross-disciplinary way. So, from a “Law & Management” perspective, it appears to be a precious tool for the management of public undertakings. Key words: European competition law, public undertakings, fair competition, “Management & law”.


2016 ◽  
Vol 3 (4) ◽  
pp. 74-109 ◽  
Author(s):  
Tomokazu Ishikawa ◽  
Sonia Morán Panero

AbstractWith reference to two recent doctoral research projects on ELF, the present article examines the characterisation of language attitudes as either stable or variable evaluative phenomena, and provides a detailed account of methodological practices that may be favoured from each ontological position. The durability of language attitudes is more specifically conceptualised as a stable (but not enduring) construct directed to a linguistic phenomenon in one thesis, and as variable and emergent forms of evaluative social practice around a language-related issue in the other. With these two different approaches in conversation, the authors consider the extent to which stability and variability of language attitudes may be two sides of the same coin, and question whether it is safe to assume a priori the inferability of stable language attitudes from the observation of evaluative practice. This article evidences the need for ELF researchers working in this area to contemplate what and how it is being researched in the name of language attitudes while having awareness of possible alternatives in any given study.


2014 ◽  
Vol 23 (01) ◽  
pp. 1450006 ◽  
Author(s):  
L. IORIO

Analytical expressions for the orbital precessions affecting the relative motion of the components of a local binary system induced by Lorentz-violating Preferred Frame Effects (PFE) are explicitly computed in terms of the Parametrized Post-Newtonian (PPN) parameters α1, α2. Preliminary constraints on α1, α2 are inferred from the latest determinations of the observationally admitted ranges [Formula: see text] for any anomalous Solar System planetary perihelion precessions. Other bounds existing in the literature are critically reviewed, with particular emphasis on the constraint [Formula: see text] based on an interpretation of the current close alignment of the Sun's equator with the invariable plane of the Solar System in terms of the action of a α2-induced torque throughout the entire Solar System's existence. Taken individually, the supplementary precessions [Formula: see text] of Earth and Mercury, recently determined with the INPOP10a ephemerides without modeling PFE, yield α1 = (0.8±4) × 10-6 and α2 = (4±6) × 10-6, respectively. A linear combination of the supplementary perihelion precessions of all the inner planets of the Solar System, able to remove the a priori bias of unmodeled/mismodeled standard effects such as the general relativistic Lense–Thirring precessions and the classical rates due to the Sun's oblateness J2, allows to infer α1 = (-1 ± 6) × 10-6, α2 = (-0.9 ± 3.5) × 10-5. Such figures are obtained by assuming that the ranges of values for the anomalous perihelion precessions are entirely due to the unmodeled effects of α1 and α2. Our bounds should be improved in the near-mid future with the MESSENGER and, especially, BepiColombo spacecrafts. Nonetheless, it is worthwhile noticing that our constraints are close to those predicted for BepiColombo in two independent studies. In further dedicated planetary analyses, PFE may be explicitly modeled to estimate α1, α2 simultaneously with the other PPN parameters as well.


2008 ◽  
Vol 40 (01) ◽  
pp. 31-48
Author(s):  
Markus Kiderlen

We discuss the determination of the mean normal measure of a stationary random set Z ⊂ ℝ d by taking measurements at the intersections of Z with k-dimensional planes. We show that mean normal measures of sections with vertical planes determine the mean normal measure of Z if k ≥ 3 or if k = 2 and an additional mild assumption holds. The mean normal measures of finitely many flat sections are not sufficient for this purpose. On the other hand, a discrete mean normal measure can be verified (i.e. an a priori guess can be confirmed or discarded) using mean normal measures of intersections with m suitably chosen planes when m ≥ ⌊d / k⌋ + 1. This even holds for almost all m-tuples of k-dimensional planes are viable for verification. A consistent estimator for the mean normal measure of Z, based on stereological measurements in vertical sections, is also presented.


2019 ◽  
pp. 44-53
Author(s):  
Vadim Chuiko ◽  
Valery Atamanchuk-Angel

In this article of the Doctor of Philosophy, professor of Taras Shevchenko Kyiv National University, Chuiko Vadim Leonidovich and Atamanchuk-Angel Valerii Ivanovich is applied the principle of «first philosophy» as the foundation of the a priori prerequisites of possible cognition, which define an existence in general rather than its individual parts. This application of metaphysics made it possible to introduce methods of «universal algebra» for the implementation of humanitarian research using algebraic description with the help of three notion: plural, operations, relation. This methodological novation makes it possible to create demonstrative models of social systems, not their constructions, because constructionsare traditionally makeby using binary description that use only two notions, categories. Question: How to fill the notion of «public agreement» with the actual content? How to make all generations participate in the adoption of a social contract? How to create a new one, without destroying it entirely, maintaining stability? How to ensure a high degree of mutation — rebuilding, rebuilding and construction? Introduced in the algebraic sense, the notion of «trust» as a definition of what is necessary for the existence of a society of being as such, forms an algebra that models social relations by the operation of trust, not violence. Based on the above, we can talk about creating a mathematical politics. Matpoliticsdeal with ideal political objects. Matpolitics is the activity of a summation of algebras. These algebras differ from each other by the choice of operations. Plurals that consist of different algebras can be the carrier of the algebra. In this case, we are talking about the algebra of trust / credo, whose signature consists of the following operations: sovereignty, trust / credit, understanding of need for the Other, agreement and recursive procedures. The result of the implementation of these methodological guidelines are the answers to the following questions: How to make the concept of «social agreement» really meaningful? How can all generations (and the unborn, too) be involved in the social agreement? How to create a new one, without destroying the foundations of the existing one, to realize the idea of conservative development: restructuring and building a new one? Based on the provisions of the algebra of trust, society appears as a plurality of sovereigns — C, possessing the full range of rights to identify trust / distrust — Di, creating agreements — Yn, and for their completeness they have and understand the need for the other — Ik. The model presented is a system of treaties that are not an abstract concept of the state, but an agreement with specific elected people who have gained the trust of those to whom they temporarily render their services. Agreements are urgent, limited by time frame, with obligatory full responsibility of the parties.


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