Error Estimators for Proper Generalized Decomposition in Time-Dependent Electromagnetic Field Problems

Due to fine discretization in space and time, the simulation of transient electromagnetic phenomena results in a large system of equations. To cope with this computational effort, model order reduction techniques can be employed. To assess the accuracy of the solution of the reduced model, an error estimation is crucial. A commonly used approach consists of the evaluation of the deviation between the reduced and the full model. This yields a loss of the a-priori property of the Proper Generalized Decomposition. To overcome this problem two a-priori criteria are presented in this paper.This work was supported by the German Research Foundation (DFG) within the research project number 347941356 ”Numerical Analysis of Electromagnetic Fields by Proper Generalized Decomposition in Electrical Machines”

Conditional Transgenesis Using Dimerizable Cre (DiCre)

Cre recombinase is extensively used to engineer the genome of experimental animals. However, its usefulness is still limited by the lack of an efficient temporal control over its activity. We have recently developed a conceptually new approach to regulate Cre recombinase, that we have called Dimerizable Cre or DiCre. It is based on splitting Cre into two inactive moieties and fusing them to FKBP12 (FK506-binding protein) and FRB (binding domain of the FKBP12-rapamycin associated protein), respectively. These latter can be efficiently hetero-dimerized by rapamycin, leading to the reinstatement of Cre activity. We have been able to show, using in vitro approaches, that this ligand-induced dimerization is an efficient way to regulate Cre activity, and presents a low background activity together with a high efficiency of recombination following dimerization. To test the in vivo performance of this system, we have, in the present work, knocked-in DiCre into the Rosa26 locus of mice. To evaluate the performance of the DiCre system, mice have been mated with indicator mice (Z/EG or R26R) and Cre-induced recombination was examined following activation of DiCre by rapamycin during embryonic development or after birth of progenies. No recombination could be observed in the absence of treatment of the animals, indicating a lack of background activity of DiCre in the absence of rapamycin. Postnatal rapamycin treatment (one to five daily injection, 10 mg/kg i.p) induced recombination in a number of different tissues of progenies such as liver, heart, kidney, muscle, etc. On the other hand, recombination was at a very low level following in utero treatment of DiCre×R26R mice. In conclusion, DiCre has indeed the potentiality to be used to establish conditional Cre-deleter mice. An added advantage of this system is that, contrary to other modulatable Cre systems, it offers the possibility of obtaining regulated recombination in a combinatorial manner, i.e. induce recombination at any desired time-point specifically in cells characterized by the simultaneous expression of two different promoters

Objet-structured approach to modeling problem-oriented management accounting information systems

Рассматриваются проблемно-ориентированные системы сбора и обработки учетно-аналитической информации, основное назначение которых состоит в сборе, обработке, категоризации и представлении в удобной форме информации руководителям предприятий и компаний для выработки управленческих решений. Ключевым критерием эффективности таких систем, помимо достоверности выходной информации, является уровень отражения специфики управленческого учета в конкретной организации, который зависит от качества концептуальной модели системы. Актуальность работы обусловлена необходимостью исследования теоретических аспектов моделирования эффективных проблемно-ориентированных систем обработки учетно-аналитической информации. Цель исследования: разработка концепций объектно-структурного подхода к моделированию проблемно-ориентированных систем обработки учетно-аналитической информации. Методы исследования: логистический подход, метод имитационного моделирования, метод объектно-структурного моделирования сложных производственных систем, современная концепция построения систем оперативной транзакционной обработки данных, методология объектно-ориентированного анализа. Результаты. Сформулированы и описаны принципы объектно-структурного подхода к моделированию проблемно-ориентированных систем сбора и обработки учетно-аналитической информации. Перечислены базовые концептуальные классы объектно-структурного подхода: виртуальные склады, контролеры, агрегаты и переделы. Описанные принципы объектно-структурного подхода позволяют расширить его методологические возможности для концептуального моделирования эффективных проблемно-ориентированных систем сбора и обработки учетно-аналитической информации благодаря универсальности используемой в подходе объектно-структурной модели, простоте ее адаптации к специфике управленческого учета в конкретной организации и интеграции в ее корпоративную информационную систему. На основе предлагаемого подхода разработана методология моделирования, успешно применяемая в процессе проектирования проблемно-ориентированных систем сбора и обработки учетно-аналитической информации для многопередельных производств и страховой деятельности.The paper considers the problem-oriented management accounting information systems. The main purpose of such systems is to operate functions of data gathering, processing, categorizing and reporting information for management decision-making. A key criterion for such system effectiveness in addition to the reliability of the output data is the level of reflecting the management accounting in a particular company, which depends on the quality of the system conceptual model. The urgency of the discussed issue is caused by the need to study theoretical aspects of modeling the effective problem-oriented management accounting information systems. The main aim of the study is to develop a concept of object-structured approach to modeling problem-oriented management accounting information systems. The methods used in the study: logistics approach, simulation modeling, method of object-structured modeling for complicated manufacturing systems, modern conception for online transaction processing systems design, object-oriented analysis methodology. The results. The author has stated and described the principles of object-structured approach to modeling the problem-oriented systems for gathering and processing of accounting and analytical information. The paper lists the basic conceptual classes of object-structured approach such as virtual warehouses, controllers, aggregates and conversion stages. The described principles of object-structured approach allows extending its methodological possibilities for conceptual modeling of effective problem-oriented systems for gathering and processing of accounting and analytical information through the universality of the object-structural model used in approach, the simplicity of its adapting to the specifics of management accounting in a particular company and its integration into corporate information system. Based on the approach proposed the author developed a modeling methodology applied successfully in designing problemoriented processing systems of accounting and analytical information for multistage manufacturing and insurance activity

The simulation of magnetic problems with combined fast and slow dynamics using a transient time-harmonic method

An interesting method based on a variable splitting into two time-scales, the “transient time harmonic method” is proposed allowing to compute transient phasor solutions of problems involving slow, close to quasi-static and fast dynamics simultaneously, yielding stiff properties. The time-step of the dynamic problem can be chosen larger than the fundamental time interval, resulting in an “envelope” model for the problem with the small time constant. The derivation of the FEM matrices is discussed. Examples, including a transformer operating a slow varying load and a transient coupled electromagnetic-thermal problem, are discussed

Electrodynamic finite element model coupled to a magnetic equivalent circuit

An electrodynamic field is coupled to a magnetic equivalent circuit. The electrodynamic problem is formulated by the electric vector potential and discretised by finite elements. The magnetic lumped parameter model is described in terms of unknown fluxes and magnetomotive forces. The coupled system matrix has a mixed and hybrid nature. In this presentation, the method is applied to simulate eddy current distributions in laminated material and losses in a dielectric heater

A deflated iterative solver for magnetostatic finite element models with large differences in permeability

The presence of materials with a relative large difference in permeability has a harmful influence on the convergence of Krylov subspace iterative solvers. Some slow converging components are not cured by preconditioning and correspond to eigenvectors reflecting the domains with relatively low permeable material. Approximations for those eigenvectors are determined using physical knowledge of the problem. The iterative solution process is split up in a small problem counting for the separated eigenmodes and a full-size problem out of which the slow converging modes are removed. This deflated preconditioned solver is faster converging compared to more common approaches, such as the incomplete Cholesky conjugate gradient method