scholarly journals Incorrect Simulation Results in OpenModelica

Author(s):  
V. A. Ovchinnikov ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk

An adequacy of mathematical modelling of the technical object dynamics is always a challenge, and a user can make up his mind about the modelling package using simple test schemes. The article presents the schemes that are quite common from the point of view of an inexperienced user, but have specifics in mathematical modelling. The features of the schemes are that therein failures of equilibrium equations (such as the first Kirchhoff law) and continuity (such as the second Kirchhoff law) can occur. These features can lead to incorrect results when using the OpenModelica package, while the domestic PA9 and PRADIS packages used in modelling these schemes give the correct result. The article presents two simple schemes, the simulation result of which can be a priori estimated, and provides simulation results for three packages - OpenModelica, PA9, and PRADIS.

Author(s):  
David Ryckelynck

We propose to incorporate a Response Surface (RS) approximation of variables over a parametric domain into a weak form of parametric Partial Differential Equations (PDEs). Hence a multidimensional model-reduction can be achieved. We propose a multidimensional a priori model reduction method to generate or to enrich RSs. It is coined multidimensional because the fields to forecast are defined over an augmented domain in term of dimension. They are functions of both space variables and parameters that simultaneously evolve in time. This changes the functional space related to the weak form of the PDEs and the definition of the reduced bases. It has a significant impact on the proposed model reduction method. In particular, a new point of view on interpolation of variables has to be addressed. A Multidimensional Reduced Integration Domain (MRID) is proposed to reduce the complexity of the reduced formulation. A multidimensional Hyper-Reduction method extract from the MRID truncated equilibrium equations, truncated residuals and a truncated error indicator.


Author(s):  
Galen Strawson

This chapter argues that the unqualified attribution of the radical theory to John Locke is mistaken if we are to take into account the fact that the theory allows for freaks like [Sₓ]. It first considers [I]-transfer without [P]-transfer—that is, [I]-transfer preserving personal identity—before discussing Locke's response to the idea that personal identity might survive [I]-transfer from an a priori point of view. It suggests that [I]-transfer is possible in such a way that the existence of a single Person [P₁] from t₁ to t₂ can successively (and non-overlappingly) involve the existence of two immaterial substances. It also explains how Locke's claim that [I]-transfer is possible opens up the possibility that it could go wrong, in such a way as to lead to injustice. Finally, it examines Locke's notion of “sensible creature,” which refers to a subject of experience who is a person.


Mathematics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 222
Author(s):  
Juan C. Laria ◽  
M. Carmen Aguilera-Morillo ◽  
Enrique Álvarez ◽  
Rosa E. Lillo ◽  
Sara López-Taruella ◽  
...  

Over the last decade, regularized regression methods have offered alternatives for performing multi-marker analysis and feature selection in a whole genome context. The process of defining a list of genes that will characterize an expression profile remains unclear. It currently relies upon advanced statistics and can use an agnostic point of view or include some a priori knowledge, but overfitting remains a problem. This paper introduces a methodology to deal with the variable selection and model estimation problems in the high-dimensional set-up, which can be particularly useful in the whole genome context. Results are validated using simulated data and a real dataset from a triple-negative breast cancer study.


1996 ◽  
Vol 05 (04) ◽  
pp. 427-439 ◽  
Author(s):  
RICCARDO BENEDETTI ◽  
CARLO PETRONIO

In this paper we discuss the beautiful idea of Justin Roberts [7] (see also [8]) to re-obtain the Turaev-Viro invariants [11] via skein theory, and re-prove elementarily the Turaev-Walker theorem [9], [10], [13]. We do this by exploiting the presentation of 3-manifolds introduced in [1], [4]. Our presentation supports in a very natural way a formal implementation of Roberts’ idea. More specifically, what we show is how to explicitly extract from an o-graph (the object by which we represent a manifold, see below), one of the framed links in S3 which Roberts uses in the construction of his invariant, and a planar diagrammatic representation of such a link. This implies that the proofs of invariance and equality with the Turaev-Viro invariant can be carried out in a completely “algebraic” way, in terms of a planar diagrammatic calculus which does not require any interpretation of 3-dimensional figures. In particular, when proving the “term-by-term” equality of the expansion of the Roberts invariant with the state sum which gives the Turaev-Viro invariant, we simultaneously apply several times the “fusion rule” (which is formally defined, strictly speaking, only in diagrammatic terms), showing that the “braiding and twisting” which a priori may exist on tetrahedra is globally dispensable. In our point of view the success of this formal “algebraic” approach witnesses a certain efficiency of our presentation of 3-manifolds via o-graphs. In this work we will widely use recoupling theory which was very clearly exposed in [2], and therefore we will avoid recalling notations. Actually, for the purpose of stating and proving our results we will need to slightly extend the class of trivalent ribbon diagrams on which the bracket can be computed. We also address the reader to the references quoted in [2], in particular for the fundamental contributions of Lickorish to this area. In our approach it is more natural to consider invariants of compact 3-manifolds with non-empty boundary. The case of closed 3-manifolds is included by introducing a correction factor corresponding to boundary spheres, as explained in §2. Our main result is actually an extension to manifolds with boundary of the Turaev-Walker theorem: we show that the Turaev-Viro invariant of such a manifold coincides (up to a factor which depends on the Euler characteristic) with the Reshetikhin-Turaev-Witten invariant of the manifold mirrored in its boundary.


2019 ◽  
Vol 27 (3) ◽  
pp. 317-340 ◽  
Author(s):  
Max Kontak ◽  
Volker Michel

Abstract In this work, we present the so-called Regularized Weak Functional Matching Pursuit (RWFMP) algorithm, which is a weak greedy algorithm for linear ill-posed inverse problems. In comparison to the Regularized Functional Matching Pursuit (RFMP), on which it is based, the RWFMP possesses an improved theoretical analysis including the guaranteed existence of the iterates, the convergence of the algorithm for inverse problems in infinite-dimensional Hilbert spaces, and a convergence rate, which is also valid for the particular case of the RFMP. Another improvement is the cancellation of the previously required and difficult to verify semi-frame condition. Furthermore, we provide an a-priori parameter choice rule for the RWFMP, which yields a convergent regularization. Finally, we will give a numerical example, which shows that the “weak” approach is also beneficial from the computational point of view. By applying an improved search strategy in the algorithm, which is motivated by the weak approach, we can save up to 90  of computation time in comparison to the RFMP, whereas the accuracy of the solution does not change as much.


2004 ◽  
Vol 50 (7) ◽  
pp. 113-122 ◽  
Author(s):  
C Printemps ◽  
A Baudin ◽  
T Dormoy ◽  
M. Zug ◽  
P.A. Vanrolleghem

Better controlling and optimising the plant's processes has become a priority for WWTP (Wastewater Treatment Plant) managers. The main objective of this project is to develop a simplified mathematical tool able to reproduce and anticipate the behaviour of the Tougas WWTP (Nantes, France). This tool is aimed to be used directly by the managers of the site. The mathematical WWTP model was created using the software WEST®. This paper describes the studied site and the modelling results obtained during the stage of the model calibration and validation. The good simulation results have allowed to show that despite a first very simple description of the WWTP, the model was able to correctly predict the nitrogen composition (ammonia and nitrate) of the effluent and the daily sludge extraction. Then, a second more detailed configuration of the WWTP was implemented. It has allowed to independently study the behaviour of each of four biological trains. Once this first stage will be completely achieved, the remainder of the study will focus on the operational use of a simplified simulator with the purpose of optimising the Tougas WWTP operation.


2022 ◽  
Author(s):  
Valentina Pavlova ◽  
Irina Saenkova ◽  
Yulia Shokina ◽  
Grigoriy Shokin

In this article, the results of the development of the functional fish culinary product “Thorny Skate and Cod Pie” are presented. A traditional recipe was used for making the yeast dough for the pie. The pie filling recipe was designed using Fuzzy Logic in the Matlab software package.Optimized parametersfor the selected sensory evaluation of the pie were calculated. On the basis of a priori information, key components of the filling (including the fraction of the fish components and skate meat) were chosen as the factors of interest. According to the simulation results, the optimal values werea 50/50 percentage for the first and the second factor respectively, and this providedthe maximum organoleptic assessment (five points on a five-point scale). The simulation results were compared with the results of the organoleptic evaluation of the pie made according to the optimized recipe, and their sufficient convergence was shown. The indicators of mass fraction of amine nitrogen and nitrogen of volatile bases was studied, as well as the microbiological safety indicators of flour fish culinary products, in accordance with the requirements of the Technical Regulations of the Eurasian Economic Union 040/2016 ”On the safety of fish products”. The results showed a high efficiency of the shock freezing of the semi-finished product, brought to semi-readiness, for long-term storage (120 days at a temperature no higher than minus 18 ∘C), without reducing the quality or safety of the pie. The product had a cholesterol content from 220 to 260 mg%, which allowed it to be classified as functional. The nutritional values of the product (mass fraction of protein, fat, carbohydrates, and amino acid composition) are presented. Keywords: thornyskate, functional product, pie with thornyskate and cod, shock freezing


Author(s):  
V. Y. Stepanov

The article gives a classification of the main components of unmanned aerial vehicle (UAV) systems, gives the areas in which the application of UAVs is actual in practice today. Further, the UAV is considered in more detail from the point of view of its flight dynamics analysis, the equation necessary for creating a mathematical model, as well as the model of an ordinary dynamic system as a non-stationary nonlinear controlled object, is given. Next, a description of the developed software for modeling and a description of program algorithm are given. Finally, a conclusion describes the necessary directions for further scientific researches.


Author(s):  
Сергей Александрович Лебедев ◽  
Сергей Николаевич Коськов

В статье излагается содержание двух базовых концепций неклассической философии и методологии науки: конвенционалистской и консенсуалистской теории природы научного знания и научной истины. Каждая из них является альтернативой двум основным парадигмам классической философии и методологии науки: эмпиризму (позитивизму) и рационализму. С точки зрения конвенционализма научное знание не есть ни описание чистого опыта, ни его обобщение. Но оно не является также и результатом некой априорной интуиции и чистого разума. Согласно конвенционализму научное знание - это система доказательной информации, исходные принципы которой имеют характер условных, конвенциональных истин. Отсюда следует, что любая истина в науке не категорична, а условна и имеет форму «если, то». Консенсуалистская концепция природы научного знания возникла в философии науки второй половины XX в. Она была, с одной стороны, обобщением конвенционализма, а с другой - его отрицанием. Если в конвенционализме основным субъектом научного познания является отдельный ученый, то в консенсуалистской эпистемологии таким субъектом является социальный субъект - научное сообщество. Научное познание имеет принципиально коллективный характер как в плане его получения в силу разделения научного труда, так и в плане его легитимации и оценки. Последние операции всегда являются результатом консенсуса научного сообщества. The article examines the content of two basic conceptions of non-classical philosophy and methodology of science: the conventionalist and consensual theory of the nature of scientific knowledge. Each of them is an alternative to the two main paradigms of classical philosophy and the methodology of science: empiricism (positivism) and rationalism. From the point of view of conventionalism, scientific knowledge is neither a description of pure experience nor a generalization of it. But it is also not the result of some a priori intuition and pure reason. According to conventionalism, scientific knowledge is a system of evidence-based information, the initial principles of which have the character of conditional, conventional truths. It follows that any truth in science is not categorical, but conditional and has the form «if, then». The consensual concept of the nature of scientific knowledge emerged in the philosophy of science of the second half of the twentieth century. It was, on the one hand, a generalization of conventionalism; on the other, a negation of it. If in conventionalism the main subject of scientific knowledge is an individual scientist, then in consensual epistemology such a subject is a social subject - the scientific community. Scientific knowledge has a fundamentally collective character, both in terms of its acquisition by virtue of the division of scientific work, and in terms of its legitimization and evaluation. The latest operations are always the result of a consensus of the scientific community.


2013 ◽  
pp. 100-115
Author(s):  
Stéphane Ganassali ◽  
Jean Moscarola ◽  
Francesco Casarin

Considering the large number of participants and the heterogeneity of the group, the research methodology of COBEREN has been defined in a very specific way. The authors implemented a mixed methodological approach, combining qualitative and quantitative techniques, and they used a various range of numerical, verbal, and even pictorial measurements. The scope for covering different dimensions of the consumer culture was made as open as possible but had to remain acceptable from the point of view of the survey response process. Finally, they successfully combined some a priori instructions/guidelines and some a posteriori adjustments/adaptations. This chapter introduces the data collection method, the sampling aspects, the questionnaire design and translation, implemented according to the general principles of the COBEREN methodology.


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