Objective function based ranking method for selection of optimal beam angles in IMRT

In this study, a new methodology is proposed to perform optimal selection of conductors in three-phase distribution networks through a discrete version of the metaheuristic method of vortex search. To represent the problem, a single-objective mathematical model with a mixed-integer nonlinear programming (MINLP) structure is used. As an objective function, minimization of the investment costs in conductors together with the technical losses of the network for a study period of one year is considered. Additionally, the model will be implemented in balanced and unbalanced test systems and with variations in the connection of their loads, i.e., Δ− and Y−connections. To evaluate the costs of the energy losses, a classical backward/forward three-phase power-flow method is implemented. Two test systems used in the specialized literature were employed, which comprise 8 and 27 nodes with radial structures in medium voltage levels. All computational implementations were developed in the MATLAB programming environment, and all results were evaluated in DigSILENT software to verify the effectiveness and the proposed three-phase unbalanced power-flow method. Comparative analyses with classical and Chu & Beasley genetic algorithms, tabu search algorithm, and exact MINLP approaches demonstrate the efficiency of the proposed optimization approach regarding the final value of the objective function.

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A new representation for a robot grasping quality measure

Robotica ◽

10.1017/s0263574700017811 ◽

1995 ◽

Vol 13 (3) ◽

pp. 287-295 ◽

Cited By ~ 9

Author(s):

Venugopal K. Varma ◽

Uri Tasch

Keyword(s):

Objective Function ◽

Material Properties ◽

Graphical Representation ◽

Contact Forces ◽

Geometric Constraints ◽

Objective Functions ◽

Finger Force ◽

Finger Forces ◽

Robot Grasping ◽

Selection Of

SummaryWhen an object is held by a multi-fingered hand, the values of the contact forces can be multivalued. An objective function, when used in conjunction with the frictional and geometric constraints of the grasp, can however, give a unique set of finger force values. The selection of the objective function in determining the finger forces is dependent on the type of grasp required, the material properties of the object, and the limitations of the röbot fingers. In this paper several optimization functions are studied and their merits highlighted. The paper introduces a graphical representation of the finger force values and the objective functions that enable one to select and compare various grasping configurations. The impending motion of the object at different torque and finger force values are determined by observing the normalized coefficient of friction plots.

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A More Effective Formulation of the Path Generation Mechanism Synthesis Problem

23rd Biennial Mechanisms Conference: Mechanism Synthesis and Analysis ◽

10.1115/detc1994-0200 ◽

1994 ◽

Author(s):

Irfan Ullah ◽

Sridhar Kota

Keyword(s):

Objective Function ◽

Error Function ◽

Mathematical Optimization ◽

Optimization Methods ◽

Complex Nature ◽

Mechanism Synthesis ◽

Structural Error ◽

Crank Angle ◽

The Common ◽

Selection Of

Abstract Use of mathematical optimization methods for synthesis of path-generating mechanisms has had only limited success due to the very complex nature of the commonly used Structural Error objective function. The complexity arises, in part, because the objective function represents not only the error in the shape of the coupler curve, but also the error in location, orientation and size of the curve. Furthermore, the common introduction of timing (or crank angle), done generally to facilitate selection of corresponding points on the curve for calculating structural error, has little practical value and unnecessarily limits possible solutions. This paper proposes a new objective function, based on Fourier Descriptors, which allows search for coupler curve of the desired shape without reference to location, orientation, or size. The proposed objective function compares overall shape properties of curves rather than making point-by-point comparison and therefore does not requires prescription of timing. Experimental evidence is provided to show that it is much easier to search the space of the proposed objective function compared to the structural error function.

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Performance of Static Iot Networks using RPL Objective Functions

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d9776.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 8972-8977 ◽

Cited By ~ 1

Keyword(s):

Objective Function ◽

Routing Protocol ◽

Routing Algorithms ◽

Transmission Protocol ◽

Objective Functions ◽

Lossy Networks ◽

Hop Count ◽

Efficient Data ◽

Selection Of ◽

Better Than

Internet of Things, abbreviated as IoT is a network used mainly for the communication where different devices are connected for the retrieval, examination and execution of the necessary task. One of IoT’s biggest challenge is that, they are resource-constrained. Hence, it is essential to use an efficient data transmission protocol for routing. An effective routing protocol for static IoT network is the Routing protocol for Low Power and Lossy Networks (RPL). It is essential to assess the effectiveness of the RPL with the selection of best objective function for different static model. In this paper, the performance of different routing algorithms is compared in connection with different static topologies. Hence, the objective function’s performance is compared for different topologies i.e., Butterfly, Ring and Umbrella topologies. We consider two objective functions: namely Minimum Rank with Hysteresis Objective Function (MRHOF) and Objective Function Zero (OF0). MRHOF considers Expected Transmission Count (ETX) as its metric and the metric considered under OF0 is hop count. It is observed that the objective function OF0 performs better than MRHOF for the metric of energy and successful receiving of data.

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Optimal synthesis of a four-bar linkage by method of controlled deviation

Theoretical and Applied Mechanics ◽

10.2298/tam0404265b ◽

2004 ◽

Vol 31 (3-4) ◽

pp. 265-280 ◽

Cited By ~ 14

Author(s):

Radovan Bulatovic ◽

Stevan Djordjevic

Keyword(s):

Objective Function ◽

Optimal Synthesis ◽

Straight Line ◽

Individual Comparison ◽

Four Bar Linkage ◽

The Given ◽

Initial Selection ◽

Selection Of ◽

Process Calculation ◽

Made In

This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves?s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line. .

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The organizational mechanism for the formation of programs for the renovation of cultural heritage objects on the basis of the value approach

MATEC Web of Conferences ◽

10.1051/matecconf/201819305004 ◽

2018 ◽

Vol 193 ◽

pp. 05004

Author(s):

Vera Akristiniy

Keyword(s):

Cultural Heritage ◽

Objective Function ◽

Integral Index ◽

Organizational Mechanism ◽

Definition Of ◽

State Programs ◽

Cultural Heritage Objects ◽

Efficient Selection ◽

Optimal Feature ◽

Selection Of

The article discusses the issues of preservation of cultural heritage objects due to their mass loss by creating a mechanism for the efficient selection of objects subject to renovation. The algorithm for the calculation of the degree of deterioration of the building and the integral index of value is proposed. The problem of definition of the objective function with respect to which is characterized by the objective function of the optimal feature set and the problem of definition of the target functions of state programs of renovation are solving preservation.

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A Ranking Method for the Selection of the Interior Modes of Reduced Order Resonant System Models

Volume 2: Dynamics, Vibration and Control; Energy; Fluids Engineering; Micro and Nano Manufacturing ◽

10.1115/esda2014-20607 ◽

2014 ◽

Cited By ~ 2

Author(s):

Ilaria Palomba ◽

Dario Richiedei ◽

Alberto Trevisani

Keyword(s):

Normal Modes ◽

Reduced Order Model ◽

Ranking Method ◽

Resonant System ◽

Order Model ◽

Reduced Order ◽

Design And Optimization ◽

Optimization Stage ◽

Dimensional Models ◽

Selection Of

Resonant system design and optimization is usually supported by finite element models. Large dimensional models are often needed to achieve the desired accuracy in the representation of the vibrational behaviour at the frequency of interest. Unfortunately, large dimensional models are frequently too cumbersome to be actually useful, mainly at the optimization stage. On the other hand, the choice of the most appropriate reduction strategy and dimension for a reduced-order model is generally left to designers’ experience. Having recognized the effectiveness and spreading of the Craig Bampton reduction technique, the aim of this paper is to propose a rigorous ranking method, called Interior Mode Ranking (IMR), for the selection of the interior normal modes of the full order model to be inherited by the reduced order one. The method is aimed at finding the set of interior modes of minimum dimensions which allows achieving a desired level of accuracy of the reduced order model at a frequency of interest. The method is here applied to a resonator widely employed in industry: an ultrasonic welding bar horn, which is usually designed to operate excited in resonance. The results achieved through the application of the IMR method are compared with those yielded by other ranking techniques available in literature in order to prove its effectiveness.

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A framework for optimising aspects of rotor blades

The Aeronautical Journal ◽

10.1017/s0001924000005558 ◽

2011 ◽

Vol 115 (1165) ◽

pp. 147-161 ◽

Cited By ~ 4

Author(s):

C. S. Johnson ◽

G. N. Barakos

Keyword(s):

Objective Function ◽

Stokes Equations ◽

Rotor Blades ◽

Navier Stokes ◽

Computational Framework ◽

Navier Stokes Equations ◽

Theoretical Predictions ◽

Artificial Neural ◽

Optimisation Methods ◽

Selection Of

AbstractThis work presents a computational framework for the optimisation of various aspects of rotor blades. The proposed method employs CFD combined with artificial neural networks, employed as metamodels, and optimisation methods based on genetic algorithms. To demonstrate this approach, two examples have been used, one is the optimal selection of 4- and 5-digit NACA aerofoils for rotor sections and the other is the optimisation of linear blade twist for rotors in hover. For each case, an objective function was created and the meta-model was subsequently used to evaluate this objective function during the optimisation process. The obtained results agree with real world design examples and theoretical predictions. For the selected cases, the artificial neural network was found to perform adequately though the results required a substantial amount of data for training. The genetic algorithm was found to be very effective in identifying a set of near-optimal parameters. The main CPU cost was associated with the population of the database necessary for the meta-models and this task required CFD computations based on the Reynolds-averaged Navier-Stokes equations. The framework is general enough to allow for several design or optimisation tasks to be carried out and it is based on open-source code made available by the authors.

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