Wavelet Transforms in Fractal-Based Form Tolerancing

1993 ◽  
Author(s):  
R. S. Srinivasan ◽  
Kristin L. Wood
Keyword(s):  
Wavelet Transforms ◽  
Design Research ◽  
Profile Analysis ◽  
Synthesis Method ◽  
Surface Profile ◽  
Synthesis Methods ◽  
Geometric Tolerancing ◽  
Analysis And Synthesis ◽  
Cost Implications ◽  
Profile Reconstruction

Abstract Tolerancing is a crucial problem for mechanical designers, as it has quality and cost implications on product design. Research in tolerancing has addressed specific areas of the problem. Building upon previous research, a unified approach for geometric tolerancing with fractal-based parameters has been recently proposed. This paper explores an alternative error profile analysis and synthesis method, based on wavelets, that maintains and extends the use of fractals for surface error abstraction. An overview of the theory of wavelets is provided, and the link between fractals and wavelets is established. Experimental data are used to illustrate the application of wavelet theory to surface profile reconstruction and synthesis. The synthesis methods are then implemented in the design of ball-bearing elements, demonstrating the utility of fractal-based tolerancing. Plans for further study and implementation conclude the paper.

A Form Tolerancing Theory Using Fractals and Wavelets

1997 ◽  
Vol 119 (2) ◽  
pp. 185-193 ◽  
Author(s):  
R. S. Srinivasan ◽  
K. L. Wood
Keyword(s):  
Design Research ◽  
Profile Analysis ◽  
Synthesis Method ◽  
Surface Profile ◽  
Synthesis Methods ◽  
Formal Approach ◽  
Physical Test ◽  
Geometric Tolerancing ◽  
Analysis And Synthesis ◽  
Profile Reconstruction

Tolerancing is a crucial problem for mechanical designers, as it has quality and cost implications on product design. Research in tolerancing has addressed specific areas of the problem, but lacks a theoretical basis. A formal approach for geometric tolerancing with fractal-based parameters has been recently developed. This paper presents an enhanced error profile analysis and synthesis method, based on wavelets, that maintains and extends the use of fractals for surface error abstraction. An overview of the theory of wavelets is provided, and the link between fractals and wavelets is established. Physical test data are used to illustrate the application of wavelet theory to surface profile reconstruction and synthesis. The synthesis methods are then implemented in the functional design of ball-bearing elements, demonstrating the utility of fractal-based tolerancing. Plans for further study and implementation conclude the paper.

Estimating and Extracting of the Surface Profile Waviness by Use of the Spatial Notch Filters in the Roughness Profile Analysis

2017 ◽  
Vol 371 ◽  
pp. 37-43
Author(s):  
Marcin Golabczak ◽  
Andrzej Golabczak ◽  
Andrzej Konstantynowicz
Keyword(s):  
Wavelet Transforms ◽  
Profile Analysis ◽  
Surface Profile ◽  
Good Alternative ◽  
Spatial Spectrum ◽  
Shape Estimation ◽  
Notch Filters ◽  
Machined Surface ◽  
Roughness Profile ◽  
Cutting Out

Classical surveying of the machined surface quality is performed very often with using roughness profile recording by means of contact mechanical profilometer [4-7]. Also classical attitude to the profile run elaboration is to regard it as to a curve composed of the three main components: shape – treated mostly as deterministic, waviness – treated essentially as deterministic with some probabilistic component, and roughness itself – treated to as purely probabilistic. The question is: how to estimate this three components quantitatively and extract for individual evaluation. In our works we have developed methodical procedures of profile elaboration divided into three major steps: shape estimation and extraction with using polynomials of the order fitted to the evaluated profile, waviness estimation and extraction with using spatial filtering methods employing so called notch filters, statistical roughness estimation with using the set of tests and methods devoted especially to roughness runs of the purely probabilistic type. The notch filters are filters cutting out one, well determined spatial frequency λ0 from the spectrum of frequencies related with investigated profile. The second but not less important advantage of this choose, was the phase characteristics of this filter, which tends rapidly to zero outside the “notch” band, not distorting unfiltered spatial signal. The width of cutting “notch” is controlled with using one independent variable Q. Our methodology is based upon cutting out a set of frequencies from the profile, tuned separately for to achieve as well reflection of the periodic impulse-like signal as possible, due to the well known theorem of decomposing physical, periodical signals into their harmonic components. In our researches we have employed the set of 8 filters providing us with good results even with profiles “scared” with substantial tracks of periodically acting tool. Of course, it is still possible to employ even greater number of filters, due to their low numerical complexness. Also the comparison has been performed with the profile not affected by waviness for to convince, that this type of filter simply do not affect the probabilistic roughness component. All of the profile elaboration stages have been checked due to their spatial spectrum with using classical tool – FFT transform of the roughness profile autocovariance function. As the major check of the proposed procedure correctness, i.e. proper extraction of the waviness component without disturbing of the statistical roughness parameters we assumed checking of the shape factor Rq/Ra before and after waviness extraction, which turned to be the same at the good level of accuracy. Our results, basing on simple and fundamental frequency analysis seems to be the good alternative to much complicated and time consuming analysis based on wavelet transforms in different forms.

scholarly journals Stationary Traffic as a Factor of Tourist Destination Quality and Sustainability

2021 ◽  
Vol 13 (7) ◽  
pp. 3965
Author(s):  
Robert Maršanic ◽  
Edna Mrnjavac ◽  
Drago Pupavac ◽  
Ljudevit Krpan
Keyword(s):  
Synthesis Method ◽  
Hotel Industry ◽  
Point Of View ◽  
Tourist Destination ◽  
Scientific Methods ◽  
Tourist Destinations ◽  
Analysis And Synthesis ◽  
The Republic ◽  
Method Analysis

Since the Republic of Croatia is one of the most popular European and world tourist destinations, the aim of this paper is, from the user’s (n = 596) point of view, to research the importance of stationary traffic in tourist destinations. The purpose of this paper is to point out the possibilities of improving the tourist destination quality and sustainability through an adequate parking service. In order to corroborate constructed scientific hypotheses, a larger number of scientific methods were used from which a polling method, analysis and synthesis method, descriptive statistics method, t-test, and analysis of variance (ANOVA) should be singled out. The major finding of this paper indicates a relatively big importance of stationary traffic (M = 6.51; SD = 2.21) as an element of tourist destination quality. Moreover, regarding the quality of tourist destination, the results of this paper suggest that the parking space availability is more important than the way parking or parking payment are organized. Between the experienced parking problem in a tourist destination and age on one side and evaluation of the importance of stationary traffic as an element of tourist destination quality on the other side, a statistically important connection was established. Gained knowledge can be particularly helpful to hotel industry managers but also to traffic managers whose duty is to provide an adequate number of parking spaces in tourist destinations.

scholarly journals Interrelations of Synthesis Method, Polyethylene Glycol Coating, Physico-Chemical Characteristics, and Antimicrobial Activity of Silver Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2475
Author(s):  
Amirah Shafilla Mohamad Kasim ◽  
Arbakariya Bin Ariff ◽  
Rosfarizan Mohamad ◽  
Fadzlie Wong Faizal Wong
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Polyethylene Glycol ◽  
Pathogenic Bacteria ◽  
Synthesis Method ◽  
Chemical Characteristics ◽  
Synthesis Methods ◽  
Uniform Size ◽  
Transmission Electron Microscopy Analysis ◽  
Physico Chemical

Silver nanoparticles (AgNPs) have been found to have extensive biomedical and biological applications. They can be synthesised using chemical and biological methods, and coated by polymer to enhance their stability. Hence, the changes in the physico-chemical characteristics of AgNPs must be scrutinised due to their importance for biological activity. The UV-Visible absorption spectra of polyethylene glycol (PEG) -coated AgNPs displayed a distinctive narrow peak compared to uncoated AgNPs. In addition, High-Resolution Transmission Electron Microscopy analysis revealed that the shapes of all AgNPs, were predominantly spherical, triangular, and rod-shaped. Fourier-Transform Infrared Spectroscopy analysis further confirmed the role of PEG molecules in the reduction and stabilisation of the AgNPs. Moreover, dynamic light scattering analysis also revealed that the polydispersity index values of PEG-coated AgNPs were lower than the uncoated AgNPs, implying a more uniform size distribution. Furthermore, the uncoated and PEG-coated biologically synthesised AgNPs demonstrated antagonisms activities towards tested pathogenic bacteria, whereas no antagonism activity was detected for the chemically synthesised AgNPs. Overall, generalisation on the interrelations of synthesis methods, PEG coating, characteristics, and antimicrobial activity of AgNPs were established in this study.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

scholarly journals Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero
Keyword(s):  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Crystal Morphology ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Mos2 Nanosheets ◽  
Microwave Assisted

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.

COMPARING AND IMPROVING THE SYNTHESIS OF STATE-BASED SPECIFICATIONS FROM SCENARIO-BASED SPECIFICATIONS

2012 ◽  
Vol 22 (07) ◽  
pp. 867-890
Author(s):  
ZHIJIAN WANG ◽  
WENRUI LI ◽  
PENGCHENG ZHANG
Keyword(s):  
Synthesis Method ◽  
The State ◽  
Experimental Comparison ◽  
Synthesis Methods ◽  
User Requirements ◽  
State Machines ◽  
Analysis Method ◽  
Improved Method ◽  
Local Synthesis ◽  
Novel Algorithm

The scenario-based specifications are popularly used to capture user requirements. The state-based specifications are very appropriate to capture system design. Recently, there has been increased research interest in connecting these two kinds of specifications, called synthesis. Synthesis is a way to automatically construct the state-based specifications from the scenario-based specifications. There are two kinds of synthesis methods: global synthesis and local synthesis. Global synthesis means constructing a state-based specification for the whole system from the scenario-based specifications, while local synthesis means constructing a state-based specification for each object in the system. The two different synthesis methods have different uses and need to be systematically compared. The contributions of this paper are twofold. Firstly, we propose an improved method supporting the global and the local synthesis of state machines (a kind of state-based specifications) by using a novel algorithm for state machine execution and an algorithm similar to operator priority analysis method, which can fully automate the process of synthesis. Our synthesis method also satisfies two important properties: completeness and soundness. Secondly, to the best of our knowledge, our work does the first attempt to systematically compare global synthesis with local synthesis, and shows some insightful results of the experimental comparison between the two kinds of synthesis methods, which are valuable for the practitioners to choose an appropriate synthesis method for the analysis and verification of the system.

Management Of Enterprise Development Strategies Formation: Analysis And Synthesis Methods

2021 ◽  
Vol 38 (4) ◽  
Author(s):  
Olga Kalaman ◽  
Tetiana Stupnytska ◽  
Yurii Melnyk ◽  
Karine Doicheva
Keyword(s):  
Swot Analysis ◽  
Synthesis Methods ◽  
Enterprise Strategy ◽  
Strategy Formation ◽  
Local Synthesis ◽  
Self Organized ◽  
Analysis And Synthesis ◽  
Enterprise Activity ◽  
Brand Product

The purpose of the presented research is to analyze, systematize and formulate an enterprise strategy based on the analysis and synthesis of opportunities and threats of the external environment in combination with its strengths and weaknesses. Unconventional structuring of SWOT-factors, as well as their local synthesis for determination of the driving and inhibiting forces of the enterprise, has been offered. Ways to identify trends and patterns of external and internal environment based on a generalized model of SWOT-factors have been identified. Decisive in formulating a strategy (self-organized in nature) is a harmonization model of the goals system. General theoretical methods (analogy, abstraction, analysis and synthesis, idealization, imaginary modeling) and practical methods of research (observation, comparison, matching, analysis of statistical and other indicators) were used to solve the problems of the research. Methods such as empirical, statistical, graphical, etc. were used to process and summarize information.Thus, the approach study to the enterprise strategy formation based on the analysis and synthesis of the environment opportunities and threats in combination with its strengths and weaknesses allows to state that the development of a common structured list of major areas of enterprise activity is carried out taking into account the synthesis of all SWOT-analysis of the brand product, competitors and market segments, which allows the company to achieve a certain specific purpose of its activities.

scholarly journals PROBLEMS OF THE DEVELOPMENT OF PEASANT ECONOMIES AND FARMS IN THE MINDS OF THE LAND REFORM IN UKRAINE

2019 ◽  
pp. 113-125
Author(s):  
Olena Pimenova
Keyword(s):  
Land Reform ◽  
Agricultural Land ◽  
Graphical Method ◽  
Historical Analysis ◽  
State Regulation ◽  
Synthesis Methods ◽  
Expert Evaluation ◽  
Farm Model ◽  
Analysis And Synthesis ◽  
The Impact

The historical analysis of the development of national forms of economy has been carried out. It has been determined that the most economically advantageous for society, vital, rational, socio-ecological-economic forms of economy are peasant economies and farms. The methodological basis of the study as to the identification of rational and effective forms of economy are general scientific methods, including methods of historical analysis, generalization, comparison, analysis and synthesis, methods of expert evaluation, graphical method. In the course of the research, the methods of historical analysis, generalization, analysis and synthesis were used in carrying out a retrospective analysis, in particular the research of scientific opinion on the effectiveness of such forms of economy as peasants and farms and the impact of land reform on their development; the method of expert evaluation in the survey of peasants and representatives from the administration of Radomyshl region of Zhytomyr oblast to determine their opinion – how the land reform will affect on the development of peasants and farms; graphical method for constructing tables and graphs. The study of the world experience in agriculture confirmed that the development of the farm model as a priority model of economy in agriculture is possible only with the active support of a state, as an institution that regulates land use through administrative and economic measures and provides legislation through limitation of purchase of land and the potential withdrawal of this land from agricultural circulation, and also involves the implementation of targeted programs through the financing of individual activity. An important function of state regulation is the conservation of the agricultural land fund. In developed countries, there are some restrictions on the land market to prevent latifundia. It is substantiated that in the course of land reform, the agrarian policy should be focused on preventing the creation of latifundia with large land tenure, as well as on the support, protection and development of peasant economies and farms as viable forms.

scholarly journals Ensuring the financial probability of the united territorial communities in the conditions of decentralization

2020 ◽  
pp. 191-199
Author(s):  
Natalia Yevtushenko ◽  
Vitalina Malyshko ◽  
Yuliia Horodnichenko
Keyword(s):  
Social Services ◽  
Technical Assistance ◽  
Synthesis Method ◽  
Well Being ◽  
Financial Resources ◽  
Territory Quality ◽  
State Budget ◽  
Complex Process ◽  
Analysis And Synthesis ◽  
General Scientific

Subject of research is the sources of funding for the social development of united territorial communities (UTC). The purpose of the article is to determine the prospects and measures to attract financial resources for the development of local communities in a decentralized environment. Methods which were used in course of research: method of system-structural analysis and synthesis, method of comparative analysis, generalization, statistical, general scientific, special methods of scientific knowledge and other research methods. Study results.The article identifies the main obstacles to effective financial support for the development of territorial communities, considers some experience in finding and raising funds for the development of territories, describes the sources of such funds. Measures that will contribute to the investment attractiveness of the territory are analyzed and substantiated. Application of results. The results of the study can be used by the united territorial communities for the formation of financial resources, as well as in higher education institutions in the teaching of economic disciplines. Conclusions. After conducting the research, it should be noted that the process of uniting territorial communities in Ukraine and, consequently, attracting financial resources to their budgets is a rather complex process and therefore requires consolidation of efforts at all levels of government and support from European partners.  Due to the reform of decentralization of management in Ukraine, capable territorial communities should be created that are able to ensure the development of the territory, quality provision of social services and promote the well-being of their residents and Ukraine in general.  It is determined that the main sources of funds for socio-economic development of UTC are: international technical assistance, additional subventions from the state budget to local budgets for the formation of community infrastructure, local taxes from businesses.

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