A More Effective Formulation of the Path Generation Mechanism Synthesis Problem

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.

scholarly journals Topology Optimization Methods for 3D Structural Problems: A Comparative Study

2021 ◽  
Author(s):  
Daniel Yago ◽  
Juan Cante ◽  
Oriol Lloberas-Valls ◽  
Javier Oliver
Keyword(s):  
Topology Optimization ◽  
Structural Optimization ◽  
Objective Function ◽  
Computational Cost ◽  
Optimization Methods ◽  
Structural Problems ◽  
Evolutionary Structural Optimization ◽  
And Topology ◽  
The Common ◽  
Computational Platform

AbstractThe work provides an exhaustive comparison of some representative families of topology optimization methods for 3D structural optimization, such as the Solid Isotropic Material with Penalization (SIMP), the Level-set, the Bidirectional Evolutionary Structural Optimization (BESO), and the Variational Topology Optimization (VARTOP) methods. The main differences and similarities of these approaches are then highlighted from an algorithmic standpoint. The comparison is carried out via the study of a set of numerical benchmark cases using industrial-like fine-discretization meshes (around 1 million finite elements), and Matlab as the common computational platform, to ensure fair comparisons. Then, the results obtained for every benchmark case with the different methods are compared in terms of computational cost, topology quality, achieved minimum value of the objective function, and robustness of the computations (convergence in objective function and topology). Finally, some quantitative and qualitative results are presented, from which, an attempt of qualification of the methods, in terms of their relative performance, is done.

Kesulitan Mahasiswa Pembelajar Pemula Bahasa Perancis dalam Memahami Gramatika

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 354
Author(s):  
Ferli Hasanah
Keyword(s):  
French Literature ◽  
French Language ◽  
First Year ◽  
The Common ◽  
French Grammar ◽  
Bahasa Indonesia ◽  
Selection Of

ABSTRAKGramatika pada setiap bahasa memiliki kekhasannya masing-masing.Mahasiswa Program Studi Sastra Perancis tahun pertama sebagai pembelajar pemulasering mengalami kesulitan dalam memahami gramatika bahasa. Kesulitan mereka tidakterlepas dari perbedaan-perbedaan mendasar pada struktur bahasa Indonesia sebagaibahasa ibu mereka dan bahasa Perancis yang tengah dipelajari. Penelitian ini dilaksanakandengan tujuan untuk mengetahui hambatan yang dimiliki mahasiswa pembelajar pemuladi Program Studi Sastra Perancis Universitas Padjadjaran dalam memahami gramatikabahasa Perancis. Metode yang digunakan dalam penelitian ini adalah metode simak dancatat. Hasil analisis ini menunjukkan bahwa kesalahan-kesalahan yang umum dilakukanpembelajar pemula ada pada penggunaan accent, konjugasi verba, partikel défini maupunindéfini, accord penanda feminin atau jamak, serta pemilihan preposisi.Kata kunci: gramatika, bahasa Perancis, konjugasiABST RACTThe grammar in every language has its own particularities. French literaturestudents in the first year as a beginner learners often have problem in understandingFrench grammar which is frequently considered difficult. Their struggle is inseparablefrom the fundamental differences between Indonesian structure as their mother tongueand the French language which being studied. This research aims to know the obstaclesof the students of beginner learners in the French Literature of Padjadjaran university inunderstanding the basic French grammar. The method used in this research is referringand taking notes method. The results of the analysis shows that the common mistakes oflearners are in the use of accents, verb conjugations, particles défini or indéfini, markeraccord feminine or plural, and the selection of prepositions.Keywords: grammar, French, conjugation

Philosophcal review of h. white̕s tropological theory in the context of the new philosophy of history

2020 ◽  
Vol 3 (152) ◽  
pp. 92-99
Author(s):  
S. M. Geiko ◽  
◽  
O. D. Lauta
Keyword(s):  
Modern Science ◽  
Historical Knowledge ◽  
Text Organization ◽  
The Social ◽  
History Of ◽  
Actual Material ◽  
The Common ◽  
Historical Nature ◽  
Selection Of

The article provides a philosophical analysis of the tropological theory of the history of H. White. The researcher claims that history is a specific kind of literature, and the historical works is the connection of a certain set of research and narrative operations. The first type of operation answers the question of why the event happened this way and not the other. The second operation is the social description, the narrative of events, the intellectual act of organizing the actual material. According to H. White, this is where the set of ideas and preferences of the researcher begin to work, mainly of a literary and historical nature. Explanations are the main mechanism that becomes the common thread of the narrative. The are implemented through using plot (romantic, satire, comic and tragic) and trope systems – the main stylistic forms of text organization (metaphor, metonymy, synecdoche, irony). The latter decisively influenced for result of the work historians. Historiographical style follows the tropological model, the selection of which is determined by the historian’s individual language practice. When the choice is made, the imagination is ready to create a narrative. Therefore, the historical understanding, according to H. White, can only be tropological. H. White proposes a new methodology for historical research. During the discourse, adequate speech is created to analyze historical phenomena, which the philosopher defines as prefigurative tropological movement. This is how history is revealed through the art of anthropology. Thus, H. White’s tropical history theory offers modern science f meaningful and metatheoretically significant. The structure of concepts on which the classification of historiographical styles can be based and the predictive function of philosophy regarding historical knowledge can be refined.

Peculiarities of the juvenile period of the native Chechen genotypes of willow leaf pear (Pyrus salicifolia Pall.)

2020 ◽  
Vol 62 ◽  
pp. 32-38
Author(s):  
E. A. Dolmatov ◽  
R. B. Borzayev ◽  
A. N. Shaipov
Keyword(s):  
Chestnut Soil ◽  
Crop Breeding ◽  
Juvenile Period ◽  
Period 2 ◽  
Russian Research Institute ◽  
The Common ◽  
One Year ◽  
First Time ◽  
Selection Of ◽  
Creative Cooperation

The results of the study of the duration of the juvenile period of indigenous Chechen willow leaf pear genotypes (Pyrus salicifolia Pall.) are given in connection with the acceleration of the breeding process and the use of selected forms in pear breeding for high precocity. The studies were carried out in 2016-2019 at OOO “Orchards of Chechnya” in accordance with the Agreement on creative cooperation with the Russian Research Institute of Fruit Crop Breeding. The work was carried out in accordance with generally accepted programs and methods. The objects of the study were one-year and two-year-old pear seedlings obtained from sowing seeds of selected dwarf and low-growing local Chechen forms of willow pear (P. salicifolia Pall.), laying fruit buds on annual growths and seedlings of Caucasian pear (P. caucasica Fed.), 20 500 pcs. of each specie. The aim of the research was to study the potential of precocity of willow pear seedlings and to reveal of selected forms with the greatest degree of this trait. Stratified seeds were sown in the sowing department of the OOO “Orchards of Chechnya” production nursery in April, 2017. The seedlings were grown according to the common technology in dryland conditions on the plot with chestnut soil. The first fl owering of plants was noted in the spring, 2019. As a result of the research, for the first time on a large number of the experimental material it was found that in the off spring of the indigenous Chechen willow leaf pear genotypes, the selection of a little more than 2% of seedlings with a very short juvenile period (2 years) was possible. They are of great interest in accelerating the breeding process and in the selection of new pear varieties with high precocity. 20 willow leaf pear genotypes were selected for the further use in breeding for high precocity and as sources of the trait of short juvenile period.

scholarly journals Optimal Selection of Conductors in Three-Phase Distribution Networks Using a Discrete Version of the Vortex Search Algorithm

Computation ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 80
Author(s):  
John Fernando Martínez-Gil ◽  
Nicolas Alejandro Moyano-García ◽  
Oscar Danilo Montoya ◽  
Jorge Alexander Alarcon-Villamil
Keyword(s):  
Objective Function ◽  
Power Flow ◽  
Phase Distribution ◽  
Search Algorithm ◽  
Distribution Networks ◽  
Discrete Version ◽  
Optimal Selection ◽  
Flow Method ◽  
Three Phase ◽  
Selection Of

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.

A new representation for a robot grasping quality measure

Robotica ◽  
1995 ◽  
Vol 13 (3) ◽  
pp. 287-295 ◽  
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.

Life Augmentation of Turbine Exhaust System Compensators Through Integrated MADM Optimization Approach of Stress Based Fatigue Cycles

2021 ◽  
Author(s):  
Nitin D. Pagar ◽  
Amit R. Patil
Keyword(s):  
Exhaust System ◽  
Optimization Methods ◽  
Fractional Factorial ◽  
Design Parameters ◽  
Optimization Approach ◽  
Auxiliary Equipment ◽  
Maximum Expansion ◽  
Optimal Configurations ◽  
Selection Of ◽  
Turbine Exhaust

Abstract Exhaust expansion joints, also known as compensators, are found in a variety of applications such as gas turbine exhaust pipes, generators, marine propulsion systems, OEM engines, power units, and auxiliary equipment. The motion compensators employed must have accomplished the maximum expansion-contraction cycle life while imposing the least amount of stress. Discrepancies in the selecting of bellows expansion joint design parameters are corrected by evaluating stress-based fatigue life, which is challenging owing to the complicated form of convolutions. Meridional and circumferential convolution stress equations that influencing fatigue cycles are evaluated and verified with FEA. Fractional factorial Taguchi L25 matrix is used for finding the optimal configurations. The discrete design parameters for the selection of the suitable configuration of the compensators are analysed with the help of the MADM decision making techniques. The multi-response optimization methods GRA, AHP, and TOPSIS are used to determine the parametric selection on a priority basis. It is seen that weighing distribution among the responses plays an important role in these methods and GRA method integrated with principal components shows best optimal configurations. Multiple regression technique applied to these methods also shows that PCA-GRA gives better alternate solutions for the designer unlike the AHP and TOPSIS method. However, higher ranked Taguchi run obtained in these methods may enhance the suitable selection of different design configurations. Obtained PCA-GRG values by Taguchi, Regression and DOE are well matched and verified for the all alternate solutions. Further, it also shows that stress based fatigue cycles obtained in this analysis for the L25 run indicates the range varying from 1.13 × 104 cycles to 9.08 × 105 cycles, which is within 106 cycles. This work will assist the design engineer for selecting the discrete parameters of stiff compensators utilized in power plant thermal appliances.

Optimal Design of Composite Lightweight Rollers

1993 ◽  
Author(s):  
K. Bellendir ◽  
Hans A. Eschenauer
Keyword(s):  
Structural Analysis ◽  
Shell Theory ◽  
Analytical Procedure ◽  
Mathematical Optimization ◽  
Optimization Methods ◽  
Analysis Procedure ◽  
Various Boundary Conditions ◽  
Evaluation Models ◽  
Laminate Theory ◽  
Static Behaviour

Abstract A well-aimed layout of fibre-reinforced lightweight rollers does not only require an efficient structural analysis procedure but also the application of structural optimization methods. Therefore, an analytical procedure is introduced for the calculation of the static behaviour of cylindrical shells subject to axisymmetric and/or nonaxisymmetric loads. In the scope of this procedure, arbitrary, unsymmetrical laminates as well as various boundary conditions will be considered. Basis is the shell theory by Flügge enhanced by anisotropic constitutive equations (material law) in the scope of the classical laminate theory. By means of mathematical optimization procedures we then determine optimal lightweight rollers, using different design and evaluation models. For that purpose, coated and uncoated roller constructions as well as hybrid types made of CFRP/GFRP will be applied. Concluding, we will discuss possible improvements and advantages of anisotropic lightweight rollers in contrast to isotropic ones made of steel or aluminium.

scholarly journals Developing Soft Skills among Potential Employees: A Theoretical Review on Best International Practices

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Oleksandr Malykhin ◽  
Nataliia Oleksandrivna Aristova ◽  
Liudmyla Kalinina ◽  
Tetyana Opaliuk
Keyword(s):  
Professional Development ◽  
Theoretical Analysis ◽  
Soft Skills ◽  
The Other ◽  
Skills Development ◽  
Common Language ◽  
The Common ◽  
The One ◽  
A Company ◽  
Selection Of

The present paper addresses the issue of determining the best international practices for developing soft skills among students of different specialties through carrying out a theoretical review. Basing on literature on present-day theory the authors make an attempt to explain soft skills dichotomies, summarize existing approaches to classifying soft skills, consolidate and document best international practices for soft skills development among potential employees of different specialties including bachelor students, master students, doctoral and postdoctoral students. The data obtained in the theoretical analysis reveal that the possible ambiguities in the interpretation of the concept of “soft skills” are caused, on the one hand, by the dichotomic perception of their nature by present-day researchers and educators and, on the other hand, by the absence of the common language which makes it difficult to provide a more unified definition most satisfactory to all concerned. The authors are convinced that soft skills have a cross-cutting nature and regard them as personal and interpersonal meta-qualities and meta-abilities that are vital to any potential employee who is going to make positive contributions not only to his/her professional development but to the development of a company he/she is going to work for. The results of the conducted theoretical review clearly indicate that the absence of the unified understanding of the concept of “soft skills” is reflected in the existence of different approaches to classifying soft skills, let alone, the selection of didactic tools for developing soft skills among potential employees.

scholarly journals Performance of Static Iot Networks using RPL Objective Functions

2019 ◽  
Vol 8 (4) ◽  
pp. 8972-8977 ◽  
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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