Quantity Dimension Indexing for Design Knowledge Management

Author(s):  
Tamotsu Murakami ◽  
Yasushi Suehisa

Although many knowledge management techniques based on text expression have been developed, they are not necessarily sufficient for managing engineering design knowledge. In this paper, we propose quantity dimension indexing of design knowledge as a fundamental method for design knowledge management. Physical quantities describing physical phenomena can be represented as vectors in a seven-dimensional space where the orthogonal axes are the seven base units of the SI (The International System of Units). Because of the generality, objectivity and universality of the SI, this space covers all physical quantities that appear in the past, present and future design knowledge and design problems, and the same quantities are represented as the same vectors regardless of the differences in people, products, domains, organizations, nations and languages. We assume that the similarities of physical phenomena lead to similarities in the dimensions of quantities describing the phenomena, and propose to use this seven-dimensional vector for estimating the similarity of design knowledge from the viewpoint of physical phenomena. Based on this basic idea, we mathematically define similarity between two quantities using quantity dimensions. We prepared design knowledge examples and retrieval keys and conducted design knowledge retrieval and design knowledge similarity estimation by quantity dimension indexing and confirmed that we obtained adequate results without using a concept dictionary or thesaurus elaborated in advance, which are indispensable in the text approach.

1976 ◽  
Vol 46 (9) ◽  
pp. 623-628 ◽  
Author(s):  
George G. Stoner

Le Système International d'Unités (officially designated SI in all languages) provides a logical, interconnected framework for measurements in commerce, industry, and science, including the textile and allied fields. SI is based on only nine elemental units. Seventeen important derived units have special names. Any number of derived units is possible to meet particular needs. SI has only one unit for each type of physical quantity. Prefixes cover a range of 1036 to form multiples and submultiples. SI has explicitly distinct units for mass (the kilogram) and force (the newton). Numerous older units of pressure, energy, and power are superseded by the pascal, the joule, and the watt, respectively. Each equation defining a derived unit contains only the number 1 as the numerical factor. SI has salient advantages because it is a system of units coherent with respect to the system of physical quantities and the equations relating them.


Author(s):  
Tamotsu Murakami

AbstractA Contradiction Matrix of TRIZ that classifies problems to solve as contradictions of features is an effective framework of knowledge management for problem solving. The features, however, may have a problem of completeness because they may not cover contradictions about all physical phenomena. In addition, rigidly structured Contradiction Matrix may have a problem of searchability because a relevant contradiction may not be properly searched if a recorder and a retriever describe it differently. To solve these problems, this paper proposes a semistructured contradiction matrix using not TRIZ features but physical quantities in SI unit. To enable not only exact match but also partial match in searching for relevant contradictions, dimensional similarity and qualitative value similarity of physical quantity and similarity between contradictions are defined. The proposed method is implemented as software in Python and contradictions are described in XML and stored in a semistructured matrix. From the result of similarity calculation between stored contradictions, possible effectiveness of the proposed method is confirmed.


2019 ◽  
Vol 41 (2) ◽  
pp. 53-54
Author(s):  
Daniel Rabinovich

Abstract The International Prototype Kilogram, after 130 years of dutiful service, is finally retiring. The IPK, a golf ball-sized cylinder made of a special platinum-iridium alloy (90:10), was introduced in 1889 at the first General Conference on Weights and Measures (CGPM) near Paris to define the unit of mass using an artifact fabricated with the utmost care and precision available at the time. New units were subsequently adopted for other physical quantities such as electric current (the ampere) and temperature (the kelvin), and the increasing need for a more cohesive set of units of measurement led to the implementation of the International System of Units (SI) in 1960.


2020 ◽  
Vol 42 (4) ◽  
pp. 5-18
Author(s):  
V.P. Babak ◽  
A.A. Zaporozhets ◽  
Y.V. Kuts ◽  
L.M. Scherbak

It is known that deterministic and probabilistic models of measured quantities, processes and fields, as well as physical and probabilistic measures, make it possible to form a measurement result, to provide it with the properties of objectivity and reliability. On their basis, the measuring instruments necessary for obtaining new knowledge and maintaining the process of technological development of production are being developed and improved. Therefore, the issues of improving and developing models and measures in measurement methodology play an increasingly important role in achieving high measurement accuracy and expanding the areas of their application. The article is devoted to the features and results of the study of the application of models and measures in measurements. It is shown that the physical correctness and the need for setting up measuring experiments, performing tasks and conditions for their implementation, substantiating adequate models and measures significantly affect the obtained measurement result. The features of the modern methodology of using models of signals and fields and measures for evaluating the results of measuring physical quantities, including thermophysical ones, which are represented by random quantities and angles are presented. In the general case, a measure is a countably additive set function that acquires only negative values ​​in any way, including infinity. The use of charge as a mathematical model significantly expands the boundaries of the practical application of the methods of measure theory in metrology. Examples of probabilistic measures on a straight line, on a circle and a charge, as well as physical measures are considered. The concept of coordination of physical and probabilistic measures has been substantiated with the aim of a unified approach to assessing the measurement result. The joint use of physical and probabilistic measures for the formation of a measurement result allows to a certain extent overcome the problem of measurement homomorphism. An example of using a set of physical and probabilistic measures in the hardware and software modules of information and measuring systems is given. The probabilistic normalized measure is a non-physical degree, but a measure of the totality of the action of various random factors on the value and characteristics of data and the result of measurements when they are carried out. The use of a probabilistic measure in the statistical processing of measurement data makes it possible to increase the accuracy of the measurement result compared to the accuracy of the measurement data. The degree of information protection during measurements is complex. The measure is formed by many factors, the action of most of which is of a random nature. This makes it possible to determine such a measure as probabilistic, which can be applied both for individual operations, for example, transmission of measurement data via communication channels, registration of the measurement result, and for the entire measurement process as a whole. The stochastic approach in the theory of measurements is of particular importance in the case of measurements of physical quantities that have a pronounced probabilistic nature, for example, in the case of nano-measurements, the study of quantum effects, and the like. Currently, the use of the SI international system of units at the quantum level and the concept of uncertainty for evaluating measurement results, which are the foundation of measurement practice, requires a wide range of theoretical and simulation studies of measurement processes in various subject areas to form a unified measurement methodology.


Author(s):  
Tamotsu Murakami ◽  
Yosuke Kikuchi ◽  
Youji Hiraoka

In this paper, the authors propose computerized support for fault tree analysis (FTA) based on a new design knowledge management approach called quantity dimension indexing. FTA is a method of analyzing and visualizing the causes of fault events by expanding a fault event hierarchically to its possible cause events and constructing a tree diagram representing the entire structure of the problem. When a designer finds or encounters a problem during a product design and development process, an effective way of ensuring the security and safety of the product is to identify all the possible causes of the problem by FTA and fix them. Although FTA is an effective method, it is not easy for a designer to construct a complete fault tree without any misunderstanding or oversight. A promising approach for supporting FTA is to utilize a computerized knowledge management method. Although many knowledge management techniques for literal expression have been developed, they are not necessarily suitable for managing the engineering design knowledge of physical phenomena. To solve this problem, the authors propose a new design knowledge management approach called quantity dimension indexing and computerized support for FTA such as the verification of consistency of a fault tree and fault tree construction advice. By analyzing fault tree examples based on actual design activities in a company, the possible feasibility and future promise of the proposed approach are indicated.


2021 ◽  
pp. 9-13
Author(s):  
Sergey G. Semenchinskiy

The current problem in the field of electrical measurements is considered in connection with the new definitions of SI units of physical quantities adopted by the 26th General Conference on Weights and Measures in November 2018 (France, Versailles), namely, the reproduction of an ohm based on the quantum Hall effect. The reasons for the introduction in 1988 of the Klitzing constant independent of the international system of units and its cancellation in 2018 are explained. The physical foundations of the quantum Hall effect are outlined. The main indirect and direct experiments that led to the creation of an ohm standard based on the quantum Hall effect, including those carried out at VNIIMS in 1982–1986, are analyzed. Using the example of these experiments, the identity of the values of the quantized resistance for samples prepared on the basis of inversion layers in silicon, gallium arsenide and in samples of a fundamentally new substance graphene is shown. Results on the use of graphene to create standards based on the quantum Hall effect for various industries and science based on the latest advances in its production are presented.


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