scholarly journals Mission-based optimal morphing parameters for rotors with combined chord and twist morphing

2021 ◽  
Vol 1 ◽  
pp. 121
Author(s):  
Rohin Kumar Majeti ◽  
Stephan Benz
Keyword(s):  
High Speed ◽  
Optimization Problem ◽  
Pso Algorithm ◽  
Rotor Blades ◽  
Set Up ◽  
The Individual ◽  
Flight Regimes ◽  
Chord Extension ◽  
Mission Profile ◽  
Single Objective

Background: The fixed geometry rotor blades in today’s helicopters do not give the best performance throughout the duration of any mission. However, low-speed and high-speed flights have different geometrical requirements for the shape of the most efficient rotor blades. With advancements in morphing technologies, these can be applied to change the shape of the blades in different flight regimes. Methods: Two different helicopter rotor morphing concepts – namely, the linearly variable chord extension and the torque-tube based twist - under the framework of the European project SABRE were investigated for their optimal geometric parameters using a Particle Swarm Optimization (PSO) algorithm. Since the morphing parameters were dependent on the mission profile, three different missions representing typical helicopter applications were chosen. The optimization problem was posed both as single objective (power) and as multi-objective (power, tip elastic torsion and vibratory hub load). Based on the insights drawn from these investigations, a rotor was set up including both morphing concepts in a single blade. Results: The rotor with combined chord and twist morphing was shown to have better performance than the baseline blade, while keeping the penalty on the elastic torsion and vibration of the rotor to a minimum. Conclusions: Chord and twist are both important parameters determining the efficiency of a rotor blade. Since they have non-overlapping requirements, combining the two morphing concepts into a single blade can yield higher performance than the individual ones.

Strategic Behavior and Optimization in an Unobservable Constant Retrial Queue with Balking and Set-Up Time

2020 ◽  
Vol 8 (3) ◽  
pp. 273-290
Author(s):  
Linlin Wang ◽  
Liwei Liu ◽  
Zhen Wang ◽  
Xudong Chai
Keyword(s):  
Strategic Behavior ◽  
Optimization Problems ◽  
Retrial Queue ◽  
Pso Algorithm ◽  
Operating Costs ◽  
Welfare Maximization ◽  
Social Welfare Maximization ◽  
Set Up ◽  
The Individual ◽  
Steady State Solutions

AbstractAn M/M/1 constant retrial queue with balking customers and set-up time is considered. Once the system becomes empty, the server will be turned down to reduce operating costs, and it will be activated only when there is a customers arrives. In this paper, the almost unobservable case is studied, in which the information of the queue length is unavailable, whereas the state of the server can be obtained. Firstly, the steady state solutions are derived and the individual equilibrium strategies are analyzed. In addition, social optimization problems, including cost analysis and social welfare maximization are investigated by using the PSO algorithm. Finally, by appropriate numerical examples, the sensitivity of some main system parameters is shown.

Experimental and Numerical Flutter Investigation of the 1st Stage Rotor in 4-Stage High Speed Compressor

2008 ◽  
Author(s):  
E. Johann ◽  
B. Mu¨ck ◽  
J. Nipkau
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Experimental Tests ◽  
Rotor Blades ◽  
Test Facility ◽  
Nodal Diameter ◽  
Pressure Transducers ◽  
Multistage Compressor ◽  
Set Up ◽  
Forced Responses

Experimental tests were performed to investigate flutter behaviour of the transonic rotor in a high-speed multistage compressor test facility. Besides the acquisition of overall performance parameters the rig was equipped with special instrumentation such as strain gauges, tip-timing system and dynamic pressure transducers. The 4-stage compressor comprises 3 variable vanes. The instrumentation was able to measure stall and flutter and forced responses of the rotor blades. The experimental data was used to validate the in-house aeroelastic solver. During testing flutter was triggered intentionally at part speed conditions with malscheduled variable vanes. The malschedule changed the flow incidences for the relevant rotor and induced flutter. An aeroelastic simulation was set up according to the flutter conditions found during the experiment. The measured boundary conditions were used to set up the aeroelastic simulation. The calculation shows the torsion mode with a negative aerodynamic damping which confirms the test results. The only difference between test and prediction is the nodal diameter, at which the flutter occurs.

A Multi-Objective PSO Algorithm Based Niche Technique for Service-Workflows Scheduling

2013 ◽  
Vol 811 ◽  
pp. 487-494 ◽  
Author(s):  
Xiao Dong Zhang ◽  
Jin Cheng Zhang ◽  
Fan Yu Zeng
Keyword(s):  
Optimization Problem ◽  
Cost Optimization ◽  
Pso Algorithm ◽  
Optimal Solutions ◽  
Time Cost ◽  
High Quality ◽  
Multi Objective ◽  
Pareto Sets ◽  
External Population ◽  
Single Objective

Time-cost optimization problem in service-workflows is a widely existing problem hard to be solved in practical systems. In this paper, an Niche Technique multi-objective PSO method is proposed. Generating initial optimal solutions with single-objective. External Population and Niche Technique and Meshing hybrid method is introduced to obtain an evenly distributed Pareto set. Experimental results prove that the proposed algorithm is efficient and effective. For various characteristic instances, more evenly distributed Pareto Sets are obtained with high quality.

The Kinematical Performance Analysis of a Kind of Parallel Turning-Grinding Machine

2010 ◽  
Vol 126-128 ◽  
pp. 796-801
Author(s):  
Suo Xian Yuan ◽  
Xue Long Wen ◽  
Ming Hu
Keyword(s):  
Parallel Mechanism ◽  
High Speed ◽  
Spare Parts ◽  
Reconfigurable Manufacturing ◽  
Motion Modeling ◽  
Large Space ◽  
New Type ◽  
Set Up ◽  
Grinding Machine ◽  
The Individual

This paper presents a new type of two 2-DOF Parallel 2PRR institution, with the unique advantages such as simple motion modeling and easy calculation of the positive and negative solution, operating a large space, simple structure and easy to control, etc. This parallel mechanism can not only be used for the development of glass cutting, grinding materials, milling, processing equipment, spare parts and other planes, but also can be used as a multi-DOF hybrid machine tool flat actuator parallel mechanism which can give full play the advantages of strong reconfiguration, with the main different combinations of auxiliary bodies and set up to meet the individual needs of the user reconfigurable manufacturing cell to be more complex parts processing and high-speed machining.

scholarly journals Optimizing the Shunting Schedule of Electric Multiple Units Depot Using an Enhanced Particle Swarm Optimization Algorithm

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jiaxi Wang ◽  
Boliang Lin ◽  
Junchen Jin
Keyword(s):  
Particle Swarm Optimization ◽  
High Speed ◽  
Optimization Problem ◽  
Particle Swarm Optimization Algorithm ◽  
Programming Model ◽  
Particle Swarm ◽  
Pso Algorithm ◽  
Swarm Optimization ◽  
Enhanced Particle Swarm Optimization ◽  
Multiple Units

The shunting schedule of electric multiple units depot (SSED) is one of the essential plans for high-speed train maintenance activities. This paper presents a 0-1 programming model to address the problem of determining an optimal SSED through automatic computing. The objective of the model is to minimize the number of shunting movements and the constraints include track occupation conflicts, shunting routes conflicts, time durations of maintenance processes, and shunting running time. An enhanced particle swarm optimization (EPSO) algorithm is proposed to solve the optimization problem. Finally, an empirical study from Shanghai South EMU Depot is carried out to illustrate the model and EPSO algorithm. The optimization results indicate that the proposed method is valid for the SSED problem and that the EPSO algorithm outperforms the traditional PSO algorithm on the aspect of optimality.

Patient Scheduling — (Bibliography)

1977 ◽  
Vol 16 (02) ◽  
pp. 112-115 ◽  
Author(s):  
C. O. Köhler ◽  
G. Wagner ◽  
U. Wolber
Keyword(s):  
Information Processing ◽  
Medical Care ◽  
Medical Informatics ◽  
Relevant Literature ◽  
Patient Scheduling ◽  
Individual Scientist ◽  
Set Up ◽  
The Individual ◽  
New Literature ◽  
Current Systems

The entire field of information processing in medicine is today already spread out and branched to such an extent that it is no longer possible to set up a survey on relevant literature as a whole. But even in narrow parts of medical informatics it is hardly possible for the individual scientist to keep up to date with new literature. Strictly defined special bibliographies on certain topics are most helpful.In our days, problems of optimal patient scheduling and exploitation of resources are gaining more and more importance. Scientists are working on the solution of these problems in many places.The bibliography on »Patient Scheduling« presented here contains but a few basic theoretical papers on the problem of waiting queues which are of importance in the area of medical care. Most of the papers cited are concerned with practical approaches to a solution and describe current systems in medicine.In listing the literature, we were assisted by Mrs. Wieland, Mr. Dusberger and Mr. Henn, in data acquisition and computer handling by Mrs. Gieß and Mr. Schlaefer. We wish to thank all those mentioned for their assistance.

Formation of Standing Waves in Radial Tires

1984 ◽  
Vol 12 (1) ◽  
pp. 44-63 ◽  
Author(s):  
Y. D. Kwon ◽  
D. C. Prevorsek
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Unit Length ◽  
Standing Waves ◽  
Rolling Resistance ◽  
Damping Coefficient ◽  
Circular Membrane ◽  
Critical Speeds ◽  
Steel Cord ◽  
The Individual

Abstract Radial tires for automobiles were subjected to high speed rolling under load on a testing wheel to determine the critical speeds at which standing waves started to form. Tires of different makes had significantly different critical speeds. The damping coefficient and mass per unit length of the tire wall were measured and a correlation between these properties and the observed critical speed of standing wave formation was sought through use of a circular membrane model. As expected from the model, desirably high critical speed calls for a high damping coefficient and a low mass per unit length of the tire wall. The damping coefficient is particularly important. Surprisingly, those tire walls that were reinforced with steel cord had higher damping coefficients than did those reinforced with polymeric cord. Although the individual steel filaments are elastic, the interfilament friction is higher in the steel cords than in the polymeric cords. A steel-reinforced tire wall also has a higher density per unit length. The damping coefficient is directly related to the mechanical loss in cyclic deformation and, hence, to the rolling resistance of a tire. The study shows that, in principle, it is more difficult to design a tire that is both fuel-efficient and free from standing waves when steel cord is used than when polymeric cords are used.

scholarly journals Nudge Versus Boost: Agency Dynamics Under Libertarian Paternalism

2019 ◽  
Vol 130 (629) ◽  
pp. 1384-1415 ◽  
Author(s):  
Ralph Hertwig ◽  
Michael D Ryall
Keyword(s):  
Cognitive Biases ◽  
Policy Implications ◽  
Best Interests ◽  
Libertarian Paternalism ◽  
The Future ◽  
Set Up ◽  
The Individual

ABSTRACT Thaler and Sunstein (2008) advance the concept of ‘nudge’ policies—non-regulatory and non-fiscal mechanisms designed to enlist people's cognitive biases or motivational deficits so as to guide their behaviour in a desired direction. A core assumption of this approach is that policymakers make artful use of people's cognitive biases and motivational deficits in ways that serve the ultimate interests of the nudged individual. We analyse a model of dynamic policymaking in which the policymaker's preferences are not always aligned with those of the individual. One novelty of our set-up is that the policymaker has the option to implement a ‘boost’ policy, equipping the individual with the competence to overcome the nudge-enabling bias once and for all. Our main result identifies conditions under which the policymaker chooses not to boost in order to preserve the option of using the nudge (and its associated bias) in the future—even though boosting is in the immediate best interests of both the policymaker and the individual. We extend our analysis to situations in which the policymaker can be removed (e.g., through an election) and in which the policymaker is similarly prone to bias. We conclude with a discussion of some policy implications of these findings.

Parameter study and optimization design of a hat oblique tunnel portal

2021 ◽  
pp. 095440972110140
Author(s):  
Zijian Guo ◽  
Tanghong Liu ◽  
Wenhui Li ◽  
Yutao Xia
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Pareto Front ◽  
Optimization Problem ◽  
Optimization Method ◽  
Design Parameters ◽  
Parameter Study ◽  
Buffer Structure ◽  
Tunnel Entrance ◽  
The Ideal

The present work focuses on the aerodynamic problems resulting from a high-speed train (HST) passing through a tunnel. Numerical simulations were employed to obtain the numerical results, and they were verified by a moving-model test. Two responses, [Formula: see text] (coefficient of the peak-to-peak pressure of a single fluctuation) and[Formula: see text] (pressure value of micro-pressure wave), were studied with regard to the three building parameters of the portal-hat buffer structure of the tunnel entrance and exit. The MOPSO (multi-objective particle swarm optimization) method was employed to solve the optimization problem in order to find the minimum [Formula: see text] and[Formula: see text]. Results showed that the effects of the three design parameters on [Formula: see text] were not monotonous, and the influences of[Formula: see text] (the oblique angle of the portal) and [Formula: see text] (the height of the hat structure) were more significant than that of[Formula: see text] (the angle between the vertical line of the portal and the hat). Monotonically decreasing responses were found in [Formula: see text] for [Formula: see text] and[Formula: see text]. The Pareto front of [Formula: see text] and[Formula: see text]was obtained. The ideal single-objective optimums for each response located at the ends of the Pareto front had values of 1.0560 for [Formula: see text] and 101.8 Pa for[Formula: see text].

scholarly journals Nonconvex constrained optimization by a filtering branch and bound

2020 ◽  
Author(s):  
Gabriele Eichfelder ◽  
Kathrin Klamroth ◽  
Julia Niebling
Keyword(s):  
Constrained Optimization ◽  
Optimization Problem ◽  
Feasible Solution ◽  
Constrained Optimization Problem ◽  
Numerical Tests ◽  
Nonconvex Constrained Optimization ◽  
Objective Value ◽  
Feasible Solutions ◽  
Quality Guarantee ◽  
Single Objective

AbstractA major difficulty in optimization with nonconvex constraints is to find feasible solutions. As simple examples show, the $$\alpha $$ α BB-algorithm for single-objective optimization may fail to compute feasible solutions even though this algorithm is a popular method in global optimization. In this work, we introduce a filtering approach motivated by a multiobjective reformulation of the constrained optimization problem. Moreover, the multiobjective reformulation enables to identify the trade-off between constraint satisfaction and objective value which is also reflected in the quality guarantee. Numerical tests validate that we indeed can find feasible and often optimal solutions where the classical single-objective $$\alpha $$ α BB method fails, i.e., it terminates without ever finding a feasible solution.

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