High-Dimensional Constrained Multiobjective Optimization of a Fan Stage

2011 ◽  
Author(s):  
Marcel Aulich ◽  
Ulrich Siller
Keyword(s):  
Design Space ◽  
Surrogate Models ◽  
Expected Improvement ◽  
High Dimensional ◽  
Process Chain ◽  
Fast Evaluation ◽  
New Members ◽  
Stall Margin ◽  
Advantages And Disadvantages ◽  
The Right

A high-dimensional design space, different objectives, many constraints and a time-consuming process chain result in a complex task for any optimization tool. This paper shows methods and strategies used at DLR, Institute of Propulsion Technology, to handle this kind of problem. The present optimization task is a rotor-stator configuration with more than two hundred free design variables, two objective functions (efficiency, stall margin) and mechanical and aerodynamic constraints (mass flow, eigenfrequencies, etc.). The process chain consists of geometry and mesh generation, FEM-and 3D-CFD calculations for different operating points. After defining the setup and explaining the initial already 3-D-preoptimized configuration, the CFD/FEM optimization tool is described. This tool calculates the complete CFD/FEM process chain and creates new designs (also called members) by using an evolutionary algorithms. Parallel to the CFD/FEM optimization a program based on surrogate models is running. By using surrogate models a fast evaluation of new members is enabled. So a database of new members can be created quickly. Based on this database a set of new members is built. This is send to the CFD/FEM optimization tool, where the complete CFD/FEM process chain is applied. After the CFD/FEM evaluation process, these member are used to train the surrogate models again. This procedure repeats until the optimization goals are reached. In the next part of this paper the implemented surrogate models are discussed. Both neural networks and Kriging models have advantages and disadvantages compared to each other. It is important to understand them to choose the right model at the right time of optimization. The main focus of this paper is on the selection criterion for new members. This criterion has two targets: push the performance of the fan stage and enhance the surrogate models. At first sight these targets seem to be contrary, but the surrogate models do not predict a single mean value for an objective. They offer a density distribution of the potential objective values. That allows calculation of the Paretofront enhancement (ParetoEnSet) for a set of new members. ParetoEnSet is the expected area gain of a set of members to the current Paretofront. This criterion based on the already known expected improvement. It is shown, that ParetoEnSet can rise, when the uncertainty of an prediction increases. The uncertainty is estimated by a surrogate model. So new members tend to explore the design space, where the predicted uncertainty is huge. These members are favorable for improving the surrogate models. In addition, it is easy to couple constraints with ParetoEnSet. In the last section the results of the optimization are illustrated. Compared to baseline design the optimized stage accomplishes a notable improvement in efficiency by obtaining the stall margin and fulfilling multi aerodynamical and mechanical constraints.

Aerodynamic Optimization of the Low-Pressure Turbine Module: Exploiting Surrogate Models in a High-Dimensional Design Space

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Lieven Baert ◽  
Emmanuel Chérière ◽  
Caroline Sainvitu ◽  
Ingrid Lepot ◽  
Arnaud Nouvellon ◽  
...  
Keyword(s):  
Data Mining ◽  
Design Space ◽  
Low Pressure ◽  
Surrogate Models ◽  
High Dimensional ◽  
Efficiency Gain ◽  
Aerodynamic Optimization ◽  
Component Design ◽  
Efficient Data ◽  
Lp Turbine

Abstract Further improvement of state-of-the-art low-pressure (LP) turbines (LPTs) has become progressively more challenging. LP design is more than ever confronted to the need to further integrate complex models and to shift from single-component design to the design of the complete LPT module at once. This leads to high-dimensional design spaces and automatically challenges their applicability within an industrial context, where computing resources are limited and the cycle time is crucial. The aerodynamic design of a multistage LP turbine is discussed for a design space defined by 350 parameters. Using an online surrogate-based optimization (SBO) approach, a significant efficiency gain of almost 0.5pt has been achieved. By discussing the sampling of the design space, the quality of the surrogate models, and the application of adequate data mining capabilities to steer the optimization, it is shown that despite the high-dimensional nature of the design space, the followed approach allows to obtain performance gains beyond target. The ability to control both global as well as local characteristics of the flow throughout the full LP turbine, in combination with an agile reaction of the search process after dynamically strengthening and/or enforcing new constraints in order to adapt to the review feedback, not only illustrates the feasibility but also the potential of a global design space for the LP module. It is demonstrated that intertwining the capabilities of dynamic SBO and efficient data mining allows to incorporate high-fidelity simulations in design cycle practices of certified engines or novel engine concepts to jointly optimize the multiple stages of the LPT.

Aerodynamic Optimisation of the Low Pressure Turbine Module: Exploiting Surrogate Models in a High-Dimensional Design Space

2019 ◽  
Author(s):  
Lieven Baert ◽  
Ingrid Lepot ◽  
Caroline Sainvitu ◽  
Emmanuel Chérière ◽  
Arnaud Nouvellon ◽  
...  
Keyword(s):  
Data Mining ◽  
Design Space ◽  
Low Pressure ◽  
Surrogate Models ◽  
High Dimensional ◽  
Efficiency Gain ◽  
Component Design ◽  
Efficient Data ◽  
Complex Models ◽  
Lp Turbine

Abstract Further improvement of state-of-the-art Low Pressure (LP) turbines has become progressively more challenging. LP design is more than ever confronted to the need to further integrate complex models and to shift from single component design to the design of the complete LPT module at once. This leads to high-dimensional design spaces and automatically challenges its applicability within an industrial context, where CPU resources are limited and the cycle time crucial. The aerodynamic design of a multistage LP turbine is discussed for a design space defined by 350 parameters. Using an online surrogate-based optimisation (SBO) approach a significant efficiency gain of almost 0.5pt has been achieved. By discussing the sampling of the design space, the quality of the surrogate models, and the application of adequate data mining capabilities to steer the optimisation, it is shown that despite the high-dimensional nature of the design space the followed approach allows to obtain performance gains beyond target. The ability to control both global as well as local characteristics of the flow throughout the full LP turbine, in combination with an agile reaction of the search process after dynamically strengthening and/or enforcing new constraints in order to adapt to the review feedback, illustrates not only the feasibility but also the potential of a global design space for the LP module. It is demonstrated that intertwining the capabilities of dynamic SBO and efficient data mining allows to incorporate high-fidelity simulations in design cycle practices of certified engines or novel engine concepts to jointly optimise the multiple stages of the LPT.

scholarly journals An approximate high-dimensional optimization method using hierarchical design space reduction strategy

2021 ◽  
Vol 39 (2) ◽  
pp. 292-301
Author(s):  
Pengcheng Ye ◽  
Congcong Wang ◽  
Guang Pan
Keyword(s):  
Design Space ◽  
Optimization Method ◽  
Surrogate Models ◽  
Black Box ◽  
High Dimensional ◽  
Hierarchical Design ◽  
Reduction Strategy ◽  
Space Reduction ◽  
Ensemble Of Surrogates ◽  
Dimensional Optimization

To overcome the complicated engineering model and huge computational cost, a hierarchical design space reduction strategy based approximate high-dimensional optimization(HSRAHO) method is proposed to deal with the high-dimensional expensive black-box problems. Three classical surrogate models including polynomial response surfaces, radial basis functions and Kriging are selected as the component surrogate models. The ensemble of surrogates is constructed using the optimized weight factors selection method based on the prediction sum of squares and employed to replace the real high-dimensional black-box models. The hierarchical design space reduction strategy is used to identify the design subspaces according to the known information. And, the new promising sample points are generated in the design subspaces. Thus, the prediction accuracy of ensemble of surrogates in these interesting sub-regions can be gradually improved until the optimization convergence. Testing using several benchmark optimization functions and an airfoil design optimization problem, the newly proposed approximate high-dimensional optimization method HSRAHO shows improved capability in high-dimensional optimization efficiency and identifying the global optimum.

scholarly journals Analysis of Advantages and Disadvantages of the Location Methods of International Auricular Acupuncture Points

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Pei-Jing Rong ◽  
Jing-Jun Zhao ◽  
Lei Wang ◽  
Li-Qun Zhou
Keyword(s):  
Research Quality ◽  
Auricular Acupuncture ◽  
Acupuncture Points ◽  
Location Method ◽  
International Standard ◽  
Advantages And Disadvantages ◽  
International Standardization ◽  
The Right ◽  
Auricular Therapy ◽  
Location Methods

The international standardization of auricular acupuncture points (AAPs) is an important basis for auricular therapy or auricular diagnosis and treatment. The study on the international standardization of AAPs has gone through a long process, in which the location method is one of the key research projects. There are different points of view in the field of AAPs among experts from different countries or regions. By only analyzing the nine representative location methods, this paper tried to offer a proper location method to locate AAPs. Through analysis of the pros and cons of each location method, the location method applied in the WFAS international standard of AAPs is thoroughly considered as an appropriate method. It is important to keep the right direction during developing an International Organization for Standardization (ISO) international standard of auricular acupuncture points and to improve the research quality of international standardization for AAPs.

Aerodynamic Efficiency Optimization of the 1st Stage of Transonic High Pressure Turbine through Lean and Sweep Angles

2019 ◽  
Vol 36 (3) ◽  
pp. 245-256
Author(s):  
Yoonki Kim ◽  
Sanga Lee ◽  
Kwanjung Yee ◽  
Young-Seok Kang
Keyword(s):  
High Pressure ◽  
Surrogate Model ◽  
Design Space ◽  
Latin Hypercube Sampling ◽  
Expected Improvement ◽  
Total Efficiency ◽  
High Pressure Turbine ◽  
Sweep Angle ◽  
Design Variables ◽  
Optimal Latin Hypercube Sampling

Abstract The purpose of this study is to optimize the 1st stage of the transonic high pressure turbine (HPT) for enhancement of aerodynamic performance. Isentropic total-to-total efficiency is designated as the objective function. Since the isentropic efficiency can be improved through modifying the geometry of vane and rotor blade, lean angle and sweep angle are chosen as design variables, which can effectively alter the blade geometry. The sensitivities of each design variable are investigated by applying lean and sweep angles to the base nozzle and rotor, respectively. The design space is also determined based on the results of the parametric study. For the design of experiment (DoE), Optimal Latin Hypercube sampling is adopted, so that 25 evenly distributed samples are selected on the design space. Sequentially, based on the values from the CFD calculation, Kriging surrogate model is constructed and refined using Expected Improvement (EI). With the converged surrogate model, optimum solution is sought by using the Genetic Algorithm. As a result, the efficiency of optimum turbine 1st stage is increased by 1.07 % point compared to that of the base turbine 1st stage. Also, the blade loading, pressure distribution, static entropy, shock structure, and secondary flow are thoroughly discussed.

Mikor és hogyan integráljuk az onkológiai és a palliatív ellátást?

2021 ◽  
Vol 162 (44) ◽  
pp. 1769-1775
Author(s):  
Orsolya Horváth ◽  
Enikő Földesi ◽  
Katalin Hegedűs
Keyword(s):  
Palliative Care ◽  
Care Providers ◽  
Yale University ◽  
Early Integration ◽  
Advantages And Disadvantages ◽  
Referral Criteria ◽  
Number Of Patients ◽  
Oncology Care ◽  
The Right

Összefoglaló. A palliatív ellátások korai bevonása az onkológiai betegek ellátásába előnnyel jár mind a beteg életminősége, mind a kezelés színvonala, mind a költséghatékonyság szempontjából. Szükség van egy olyan modellre, mely alapján a megfelelő időben, a megfelelő beteg a megfelelő minőségű palliatív ellátásban részesül. Ebben a közleményben a palliatív ellátás korai integrációjának előnyei, szintjei és a speciális palliatív ellátás fogalmának ismertetése után a leginkább elterjedt beutalási modellek előnyeit és hátrányait mutatjuk be a nemzetközi szakirodalom alapján. A speciális palliatív ellátást igénylő betegek kiszűrésére szolgáló, prognózisalapú modellek hátránya, hogy nincs elég kapacitás az ilyen módon beutalt nagyszámú beteg ellátására, ezért széles körben nem terjedtek el. A tüneteken alapuló modellek sokszor bonyolultak és a mindennapi klinikai gyakorlatban nem használatosak. Az új kutatások alapján egyszerű, gyakorlatias kérdéssorokat alkalmaznak, melyekkel könnyen kiemelhetők, akik profitálnak a speciális palliatív intervencióból. Ezek közül a Yale egyetemi és a PALLIA -10 modellt ismertetjük részletesen. Amennyiben az aktív onkológiai ellátást végzők a megfelelő palliatív beutalási kritériumokat ismerik és alkalmazzák, a betegek időben jutnak a megfelelő komplex kezeléshez anélkül, hogy a palliatív ellátórendszer túlterhelődne. Orv Hetil. 2021; 162(44): 1769–1775. Summary. Early integration of palliative care into the trajectory of cancer care brings advantages into the patients’ quality of life, the level of care and cost-efficiency, too. On the basis of a predefined model, the right patient may receive the right level of palliative care at the right time. Having defined the advantages, the levels of early integration of palliative care and the concept of special palliative care, we also aim to describe the advantages and disadvantages of the most common referral models on the basis of international literature in this article. The drawback of prognosis-based models to identify patients needing special palliative care is the lack of capacity to provide care for the large number of patients so recognised; therefore they have not become widespread. Needs-based models tend to be complicated and thus rarely applied in everyday clinical practice. On the basis of new researches, simple, pragmatic questionnaires are utilised through which the patients who could benefit from special palliative care interventions are easy to identify. Here we give a detailed report of the Yale University and PALLIA-10 models. On condition that appropriate palliative referral criteria are known and applied by active oncology care providers, patients may receive adequate complex care without the palliative care system being overloaded. Orv Hetil. 2021; 162(44): 1769–1775.

The role of motivation in talent selection and ­development in competitive sport

2021 ◽  
Keyword(s):  
Measurement Instrument ◽  
Psychological Characteristics ◽  
Advantages And Disadvantages ◽  
Current State ◽  
Talent Selection ◽  
Comprehensive Picture ◽  
Performance Development ◽  
The Right

The early and long-term development of promising young athletes is a decisive factor in being internationally competitive in top-level sports. Among the multitude of talent criteria suggested in the literature, motivation plays a prominent role in the area of psychological characteristics. It is recognised in practice and research as a relevant criterion for performance development across all sports. This article provides an overview of the current state of talent research in the field of motivation. First, the most common theories of motivation in competitive sports are described, then different measurement methods and their advantages and disadvantages as well as the predictive value of motivation for athletic performance are discussed. Finally, implications for practice are suggested. It can be summarised that motivation in sport is conceptualised and operationalised in different ways and that the decision for the right measurement instrument depends on the goal of the assessment. To get a comprehensive picture of an athlete’s motivational status, it is useful to assess several aspects of motivation through different methods.

Symmetric Single Rod Cylinders With Variable Piston Area? A Comprehensive Approach to the Right Solution

2018 ◽  
Author(s):  
Giacomo Kolks ◽  
Jürgen Weber
Keyword(s):  
Experimental Validation ◽  
Design Space ◽  
Solution Space ◽  
Hydraulic Cylinder ◽  
Load Cycle ◽  
Displacement Control ◽  
Comprehensive Description ◽  
Subsequent Step ◽  
Variable Displacement ◽  
The Right

In contrast to rotational hydraulic displacement units, such as pumps or motors, conventional hydraulic cylinder actuators do not allow a continuous variation of their displacement quantity: the piston area is regarded constant. In order to adapt to varying load and velocity requirements in a load cycle under torque restrictions of the driving motor, cylinder drives often implement pumps with variable displacement. In this paper, cylinders with discretely variable effective piston area by means of variable circuitry of multi-chamber cylinders are discussed. Hydraulic symmetry or constant asymmetry of the hydraulic cylinder are traits of the cylinder that are required to fit the cylinder to pump structures for closed-circuit displacement control, as given in electro-hydrostatic compact drives (ECD). A methodology to generate all possible solutions of variable area cylinders under the constraint of ECD requirements is proposed. A comprehensive description of the solution space is given, based on combinatorics and solution of equation systems. The methodology dealing with abstract cylinder areas is backed up by a general approach to describe the mechanical cylinder design space to combine multiple cylinder areas in one structural unit. Examples for design of three and four area cylinders are given and results are discussed. The paper concludes with the development of a demonstrator design to allow experimental validation in a subsequent step.

scholarly journals Genome Sequences of Mycobacteriophages Jane and Sneeze, New Members of Cluster G

2017 ◽  
Vol 5 (11) ◽  
Author(s):  
Catherine M. Mageeney ◽  
Cimrin Bhalla ◽  
Charles A. Bowman ◽  
Bhavishya Devireddy ◽  
Adrienne P. Dzurick ◽  
...  
Keyword(s):  
Costa Rica ◽  
Mycobacterium Smegmatis ◽  
Mobile Element ◽  
Genome Sequences ◽  
New Members ◽  
Content Type ◽  
The Right

ABSTRACT Jane and Sneeze are newly isolated phages of Mycobacterium smegmatis mc2155 from Hillsborough, NJ, and Palo Verde, Costa Rica, respectively. Both are cluster G, subcluster G1 mycobacteriophages. Notable nucleotide differences exist between genomes in the right half, including the presence of mycobacteriophage mobile element 1 (MPME1) in Jane.

scholarly journals Profile Matching Untuk Sistem Pendukung Keputusan Pemilihan Vendor Maintenance Server dan Jaringan

2018 ◽  
Vol 5 (2) ◽  
pp. 262-269
Author(s):  
Khoirun Nisa ◽  
Entin Sutinah
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Advantages And Disadvantages ◽  
Profile Matching ◽  
Secondary Factor ◽  
Network Maintenance ◽  
Voting System ◽  
Maintenance Work ◽  
The Right

AbstrakMemilih pemasok  yang  tepat atau vendor diantara pemasok  yang  ada  adalah  isu  penting  bagi  top manajemen. Proses penentuan vendor pada PT. Gema Graha Sarana dilakukan secara manual, yang diawali dengan pengumpulan informasi melalui presentasi dari setiap calon vendor. Setelah itu dilakukan rapat pimpinan untuk membahas tentang kelebihan dan kekurangan masing-masing vendor. Rapat pimpinan perusahaan menggunakan sistem votting sehingga cara tersebut dinilai masih kurang objektif dan tidak menutup kemungkinan penilaian dilakukan secara subjektif. Saat ini sudah berkembang pesat teknologi dalam segala bidang salah satunya teknologi dalam penentuan pengambilan keputusan, oleh karena itu untuk membantu dalam pemecahan masalah tersebut perlu dilakukan sebuah  pendekatan dengan menggunakan sebuah metode sistem pendukung keputusan salah satu nya dengan menggunakan metode Profile Matching dengan tahapan yaitu menentukan kriteria, perhitungan pemetaan gap, melakukan pembobotan, perhitungan core factor dan secondary factor, perhitungan nilai total, dan perhitungan untuk menentukan perangkingan.Tujuan dari penelitian ini adalah menentukan vendor  yang cocok agar mampu menyediakan layanan jasa maintenance server dan jaringan sesuai kebutuhan. Sehingga dari tahapan-tahapan tersebut diperoleh sebuah hasil keputusan untuk memilih vendor yang akan diajak kerja sama dalam melakukan pekerjaan maintenance server dan jaringan dengan memilih PT. Nusa Network Prakarsa. Kata Kunci: Pemilihan Vendor, Profile Matching, Sistem Pendukung Keputusan. AbstractSelecting the right supplier or vendor among existing suppliers is an important issue for top management. The process of determining vendor at PT. GemaGrahaSarana, Tbk is done manually, which begins with the collection of information through the presentation of each potential vendor. After that conducted a leadership meeting to discuss the advantages and disadvantages of each vendor. Company leadership meeting using the voting system so that way is considered still less objective and did not rule out the assessment is done subjectively. Nowadays, technology has been developed in all fields, one of them is technology in determining decision making, therefore to assist in solving the problem it is necessary to do an approach by using a method of decision support system of one of them by using method matching profile with stages that is Determining Criteria , Gap Mapping Calculation, Weighting, Calculation of Core Factor and Secondary Factor, Total Value Period, and Calculation for Determining Ranking. The purpose of this research is to determine the suitable vendors to be able to provide server and network maintenance services as needed. So from these stages obtained a decision to select a vendor who will be invited to work together in doing maintenance work server and network by choosing PT. Nusa Network Prakarsa. Keywords: Vendor Selection, Profile Matching, Decision Support System.

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