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“the quality of life.”

      (b) The term quality has a long history dating back to Aristotle’s days, while the term engineering level came into being (mainly in the Russian literature) in the last 30 – 35 years. This brings up the natural question: why use a new term if we have a long-established synonymous term?

      (c) It is common knowledge that the quality of a finished product is defined by three factors: the quality of its design, the quality of its raw materials and semi-finished products, and the quality of its manufacture (that is, the extent to which its design parameters are met in manufacture).Sometimes the term engineering level refers to what is termed design quality in qualimetry.

      Then the question arises: why introduce a new term, engineering level, if we can do with the good old term, quality (or more precisely, design quality)?

      For these reasons, in the science of qualimetry (and in this ABC) the term engineering level is not used.

      The term technical excellence is an absolute synonym of engineering level. Therefore, all that was said above regarding engineering level applies to technical excellence.

      The term utility describes a property that characterises the aggregate of quantity and quality of an object (see, e.g., [1]).

      For example, the utility of two houses is greater than that of one of exactly the same quality. However, utility and quality means the same thing when applied to one unit of quantity of an object. That is to say, we can assume that quality is the utility of one unit of quantity of an object. Since the quantitative estimation toolbox is better designed for quality than for utility in what follows we will use mainly the term quality, that is to say, consider mainly objects whose number is equal to one unit.

      The term value is synonymous with utility but its use is normally restricted to the philosophical literature. All that we have said above about utility holds for value.

      Concept of use value. If as shown above, quality is the utility of an object unit (that is, a property inherent in the object),use value is the object possessing this property, i.e. utility. As applied to an object whose quantity equals unity, use value is the object possessing this property whose quantity equals unity (see [1]). As the subject matter of this ABC is the quality of an object (e.g., the quality of life) and not its quantity, hereafter the concept of use value will not be generally used and our exposition will be in relation to the concept of quality.

      The term efficiency has many different interpretations. With regard to the most commonly used one it is very close to integral quality. However, because of its ambiguity we will use it instead the term integral quality. On the other hand, since most of the statements relating to the concept of quality remain in force and applicable to the concept of integral quality, the latter will be used hereafter only in specified cases.

      We introduce some more concepts related to the concept of quality.

      Property / quality / integral quality index. Is a quantitative characteristic of a property / quality / integral quality.

      Index value. Is a specific numeric value that an index can take. For example, the values for the property index “room temperature” can be 20° С or 22° С. Here the numerals 20 or 22 are the values of the property index. Similarly the term index value can be illustrated (this time in dimensionless units) with reference to quality. Let the quality index be expressed by the symbol К^к. Then in the expression К^к = 0.68 the numeral 0.68 is the value of К^к.

      Where quality is analysed in general terms (i.e., not in a numeric but in an alphabetic form) the value of the index is expressed not by a numeral but by a lowercase letter (as opposed to the index itself, which is always denoted by a capital letter). For example, the expression K^К= k₁^K reads as follows: the quality index K^K has the value k₁^K. This applies to a quality index but also to a property index, an integral property index, etc.; to any index at all.

      After we have clarified the meanings of the basic concepts related to the term quality we can analyse concepts related to the term control, which is in practice often linked with quality (e.g., in phrases like “product quality control”).

      1.1.2. The Term Control and Its Difference from Other Similar Terms

      Let us denote a given time point byt₁and a time point in the future by t₂ (obviously, t₂>t₁). Let us denote by ΔT the time elapsed from t₁ to t₂: ΔT= t₂ – t₁.

      Let us define our terms:

      Pre-settime ΔT_SET: a time period ΔT, the value of which is pre-set by a human controller.

      Indefinite period of time ΔT_i: a time period ΔT_i the value of which is not pre-set/defined by human controller.

      Let us introduce some terms:

      Object state: the state of an object at an instant defined by its quality whose index has the value k^K.

      Given object state: the state of an object at a given (initial) instantt₁at which the value of its quality index is k₁^K.

      Future object state: the state of an object at a future instant t₂at which its quality index will be k₂^K.

      Quality variation: a value given by the expression ΔK^K = k₂^K– k₁^K.

      Pre-set quality variation ΔK^K_PRE: a quality variationΔK^K the value of which is given in advance by a human controller.

      Indefinite quality variation ΔK^K?: a quality variation ΔK^K the value of which is not given by a human controller.

      Object quality control: the transfer of an object from a given state k₁^K to a future state k₂^K at ΔK^K_PRE with in ΔT_PRE (To rephrase it, to control the quality of an object is to ensure in the object a pre-set quality variation ΔK^K_PRE with in a pre-set time ΔT_PRE).

      It follows from this definition that if any of these conditions were not met (e.g., indefinite timeΔT? instead of pre-set time ΔT_PRE or in definite quality variation ΔK^K? instead of pre-set quality variation ΔK^K_PRE is used) it would be improper to refer to it as quality control. In actual fact a different process is in progress. Table 1 shows different processes and their relation to the quality control process.

      Table 1. Kinds of processes related to variation in the quality of objects. NOTE: Lines 10 and 11 represent situations, in which quality control in the ordinary sense is indeed exercised

      Table 1 lists twelve situations differing in their combinations of ΔK^K (quality variation) and ΔT (time variation). Each has an associated process type related to quality variation, from total uncertainty to quality control, which may vary within pre-set limits within a pre-set time.

      Regrettably, in practice the term quality control is

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