To prove two results. Namely that if in a linear homogeneous bicompartmental system one compartment is measured then it is indefinable. The second one is related to the…
Abstract
Purpose
To prove two results. Namely that if in a linear homogeneous bicompartmental system one compartment is measured then it is indefinable. The second one is related to the identification of non‐linear compartmental models by mean of a linear method.
Design/methodology/approach
The first result is generalized to linear non‐homogeneous bicompartmental systems of Michaelis‐Menten (M‐M systems). The second one is related to the identification of a non‐linear compartmental model. The obtained linear system is not homogeneous and must be generalized to nonhomogeneous systems. Then the Jacobian matrix associated to the M‐M systems is identified and the M‐M parameters are deduced by continuity from the Cauchy problem's solution.
Findings
Both stated results were proved and any open linear bicompartmental system whether homogeneous or not, of the type I is identifiable.
Research limitations/implications
In compartmental analysis the exchange hypothesis allows us to represent a model of any phenomenon depending on time. Many phenomena require “the enzyme reactions” leading to the M‐M laws. These laws assert that the quantity of matter going from compartment can be defined and M‐M constants prescribed. This research considers both homogeneous and nonhomogeneous systems cases.
Practical implications
Contributes to the identification of linear and non‐linear bicompartmental systems which are of biocybernetical significance.
Originality/value
The two proven results are new and applicable.
Details
Keywords
This paper aims at identifying the closed Michaelis‐Menten (M‐M) system. The system governs many phenomena that are based on “enzyme reactions”.
Abstract
Purpose
This paper aims at identifying the closed Michaelis‐Menten (M‐M) system. The system governs many phenomena that are based on “enzyme reactions”.
Design/methodology/approach
A linearization method is used. The system, however is not homogeneous and consequently earlier identification results obtained by the author cannot be applied. The approach is to show that the closed Michaelis‐Mentan system can be approximated by a sequence of open M‐M systems. The M‐M parameters are then obtained by continuity from the Cauchy's problem solution.
Findings
The main results – the identification of a closed M‐M system is described. The linearization of the closed M‐M compartmental system led to a linear nonhomogeneous system. Earlier classical methods could not applied but the “Reasonable Biological Hypothesis” of the author allowed further study.
Research limitations/implications
This study takes a preferred theoretical aspect. A generalization to n, n≥3 is considered to be interesting because we can consider an open compartmental system having n compartments as a closed system with n+1 compartments. Further work on this generalization is contemplated.
Practical implications
This theoretical study will further increase the use compartmental analysis to modelling any phenomena depending only on time.
Originality/value
Provides a methodology for identification of M‐M system using a linear strategy.
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Keywords
Aims to study direct identification of general linear compartmental systems by means of (n−2) compartmental measures. This is based on two main results.
Abstract
Purpose
Aims to study direct identification of general linear compartmental systems by means of (n−2) compartmental measures. This is based on two main results.
Design/methodology/approach
The first result presented is related to the existence and uniqueness of identification exchange parameters in linear compartmental systems by using a direct method with less restrictive assumptions. A second result given, permits us to show that (n−2) observations are sufficient to identify the compartmental systems.
Findings
This research study describes a method which shows that in an open linear compartmental systems there exists an energy dissipation from compartmental 1 to the systems exterior. An explicit relationship between the dissipated energy and the exchange parameters was established. The results are probably perfectible and are optimal for n=3, where only an observable compartment is needed.
Practical implications
The identification of exchange parameters is easily obtained by using the matrix of the elementary masses and by solving a linear algebraic system. Among the open problems in compartmental analysis is the problem of minimizing the observable compartments which is studied in this paper.
Originality/value
The study is based on the original work of Yves Cherruault who has already presented methods for proving that a bicompartmental systems is uniquely identified. He has generalised his method for n‐compartments.
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Belkhaled Hebri, Salim Khelifa and Yves Cherruault
The purpose of this paper is to prove that under sufficient conditions the linearization method used for identifying a nonlinear bicompartmental system is stable.
Abstract
Purpose
The purpose of this paper is to prove that under sufficient conditions the linearization method used for identifying a nonlinear bicompartmental system is stable.
Design/methodology/approach
The problem of identifying a nonlinear compartmental system appears as badly stated a priori. In fact the problem is not to identify the general behavior law of exchange between compartments, but to assume these laws known such as in Michaelis‐Menten systems or in polynomial compartmental systems with coefficients that need to be identified. It has been proved previously that with a linearization method an approximation can be obtained to the identification of these nonlinear systems. To validate this method, a stability study is necessary.
Findings
Sufficient conditions are established for the evolution law of a nonlinear bicompartmental system under which the linearization method is stable, and an upper bound is given on the approximation error – with an application, in the last section to the case of an open Michaelis‐Menten system.
Originality/value
The paper is of value in establishing sufficient conditions about the evolution law of a nonlinear system in order to show that this method is stable and to give an upper bound on the approximation error.
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This paper studies the existence and uniqueness of parameters identification in linear compartmental systems using successive resolutions of linear algebraic systems. These…
Abstract
This paper studies the existence and uniqueness of parameters identification in linear compartmental systems using successive resolutions of linear algebraic systems. These results can be exploited to build up simple numerical algorithms involving only algebraic linear systems. Compartmental analysis is the main mathematical technique for modelling phenomena arising in biology and medicine.
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Mohamed Amine Hebri, Abderrahmane Rebhaoui, Gregory Bauw, Jean-Philippe Lecointe, Stéphane Duchesne, Gianluca Zito, Abdelli Abdenour, Victor Mediavilla Santos, Vincent Mallard and Adrien Maier
The purpose of this paper is to exploit the optimal performances of each magnetic material in terms of low iron losses and high saturation flux density to improve the efficiency…
Abstract
Purpose
The purpose of this paper is to exploit the optimal performances of each magnetic material in terms of low iron losses and high saturation flux density to improve the efficiency and the power density of the selected motor.
Design/methodology/approach
This paper presents a study to improve the power density and efficiency of e-motors for electric traction applications with high operating speed. The studied machine is a yokeless-stator axial flux permanent magnet synchronous motor with a dual rotor. The methodology consists in using different magnetic materials for an optimal design of the stator and rotor magnetic circuits to improve the motor performance. The candidate magnetic materials, adapted to the constraints of e-mobility, are made of thin laminations of Si-Fe nonoriented grain electrical steel, Si-Fe grain-oriented electrical steel (GOES) and iron-cobalt Permendur electrical steel (Co-Fe).
Findings
The mixed GOES-Co-Fe structure allows to reach 10 kW/kg in rated power density and a high efficiency in city driving conditions. This structure allows to make the powertrain less energy consuming in the battery electric vehicles and to reduce CO2 emissions in hybrid electric vehicles.
Originality/value
The originality of this study lies in the improvement of both power density and efficiency of the electric motor in automotive application by using different magnetic materials through a multiobjective optimization.
Details
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Cheng Peng, He Cheng, Tong Zhang, Jing Wu, Fandi Lin and Jinglong Chu
This paper aims to further develop stator permanent magnet (PM) type memory machines by providing generalized design guidelines for double-stator memory machines (DSMMs) with…
Abstract
Purpose
This paper aims to further develop stator permanent magnet (PM) type memory machines by providing generalized design guidelines for double-stator memory machines (DSMMs) with hybrid PMs. This paper discusses the design experience of DSMMs and presents a comparative study of radial magnetization (RM) and circumferential magnetization (CM) types.
Design/methodology/approach
It begins with an introduction to RM and CM operating principles and magnetization mechanisms. Then, a comparative study is conducted for one of the RM-DSMM rotor pole pairs, inner and outer stator clamping angles and low coercive force PMs thickness. Finally, the two machines’ finite element simulation performance is compared. The validity of the proposed machine structure is demonstrated.
Findings
In this paper, the double-stator structure is extended to parallel hybrid PM memory machines, and two novel DSMMs with RM and CM configurations are proposed. Two types of DSMMs have PMs and magnetizing windings on the inner stator and armature windings on the outer stator. The main difference between the two is the arrangement of PMs on the inner stator.
Originality/value
Conventional stator PM memory machines have geometrical space conflicts between the PM and armature windings. The proposed double-stator structure can alleviate these conflicts and increase the torque density accordingly. In addition, this paper contributes to comparing the arrangement of hybrid PMs for DSMMs.
Details
Keywords
Samah Elrhanimi and Laila EL Abbadi
The purpose of this paper is to present the “Assessment Model of Lean Effect” (AMLE), a theoretical model that measures Lean manufacturing implementation effect over the global…
Abstract
Purpose
The purpose of this paper is to present the “Assessment Model of Lean Effect” (AMLE), a theoretical model that measures Lean manufacturing implementation effect over the global performance of a company.
Design/methodology/approach
AMLE model is divided in two criteria types: the “Facilitators criteria” and the “Results criteria”. “Results criteria” are inspired from the European Foundation for Quality Management (EFQM), Global Reporting Initiative (GRI) and ISO 26000. The “Facilitators criteria” are based on the main philosophy of the Lean manufacturing, which is the total elimination of all types of waste. The development of the scoring scale was based on the results, approach, deployment, assessment and review (RADAR) philosophy and the experience of nine consultants from the automotive field; the choice of the consultants was based on three conditions. Furthermore, each consultant has his\her own weight according to its expertise. Lastly, the AMLE was validated via a case study set in an automotive industry company called FEBA. The validation process is divided in two different steps: the first step is related to Facilitators assessment and scoring; via the evaluation of the different projects implemented by FEBA to eliminate the different types of waste. The second step concerns Results assessment and scoring, via the evaluation of the performance measurements used by FEBA to assess the effect of the Facilitators' implementation.
Findings
The developed model (AMLE) enabled the Lean manufacturing effect assessment on the global performance of a firm from the automotive field. The case study results reveal that the aforementioned firm does not give priority to social measurements. Consequently, the performance of the firm was negatively impacted.
Research limitations/implications
The criteria of AMLE are inspired from the definition of the Lean manufacturing given by Taiichi Ohno, from ISO 26000 and from GRI; meaning that these criteria could be adjusted if other references existed or developed. In addition, the scoring rules are established according to the experience of a limited number of consultants from the automotive field. The scoring rules establishment would lead to meaningful outcomes, if the number of participants was increased. During the assessment of the global performance, the perception of the auditor plays an important role in terms of scoring because the scoring rules allow the possibility to the auditor to give from the minimum to the maximum of the score, according to his perception and experience. For the case study, the validation of the developed model requires starting with the “Facilitators” implementation process and then measure the generated global performance. However, due to time constraints and limited opportunities for new projects, the validation was based only on existing projects managed by the firm. To address the study limitations, it is envisaged to detail and explain the scoring rules while extending the number of consultants. Furthermore, the assessment of Lean manufacturing global performance through the AMLE model may be subjective and requires a mathematical modeling. In fact, the Lean manufacturing performance assessment via the developed model could have a degree of subjectivity; that is why the design of a mathematical model seems required.
Practical implications
The research findings may direct practitioners and decision makers to the importance of assessing the global effect of the Lean manufacturing on the overall performance of the firm. The AMLE model is a tool allowing the assessment of Lean manufacturing effect over economic, environmental and social performances.
Originality/value
The developed model is the first one assessing the global performance generated by the elimination of waste via the application of the Lean manufacturing.