294
Engineering Systems Integration
maintenance, and service. According to Taguchi, after the product is put into
use, it is society and the customer who bear the cost for low quality. However,
we distinguish between the customer’s and society’s responsibilities in contrast to those attributable to the seller. Even while the seller’s purview can be
narrowed to the Taguchi limit by eliminating all interactions with the customer after the shipping event, our general perspective considers real costs
as well as the costs of negative customer reaction. Sellers sometimes have
difficulty in capturing and accounting for money and money-equivalencies
spent by customers to deal with problems, dissatisfaction, and inconvenience
associated with low quality. The approach here of developing and applying
a quality loss function allows quantitative evaluation of losses caused by
variations in behaviors and limits of performance specifications as they consociate with various functions of the product (Choi and Langford 2008).
Since Taguchi’s quality loss function is primarily focused on manufacturing, a more general formulation of loss functions is needed beyond his quadratic formulation to assist in analysis and decision making that must be made
during other lifecycle stages of the product, including conceptualization,
research, development, integration, operations, maintenance, and disposal.
The requirement is for a quality loss function that is applicable for the lifecycle of a product or service. Further, we must tackle head-on the definition
of product function and associated performance(s). Taguchi uses a quality
loss function to evaluate product performance relative to the performance
specification. When applying Taguchi methods, performance evaluation
becomes a most demanding task that challenges managers to distinguish
carefully between processes and functions, without providing the benefit
of firm definitions and theoretical standing. The diversity of definitions of
performance, the complexity of measuring performance, and the scarcity of
generally accepted performance measures compound these problems.
In general, there are at least seven distinct, although not necessarily mutually exclusive, performance measures used in practice. These are effectiveness, efficiency, quality, productivity, quality of work life, profitability, and
innovation. Thus, performance can be defined as a concept that takes on
different meanings in different situations for different organizational systems (Kaplan and Norton 1992, 1993, 1996; Kumpe and Bolwijn 1994). For
example, efficiency, quality, time, innovation, and contribution to profit are
often used as performance or effectiveness measures. Taguchi used quality
(i.e., loss) as a performance measure for evaluating product performance.
When referring to EMMI, performance can be defined as the net work
accomplished during a period t. For example, the net work accomplished
during a period t is equal to the amount of work “completed” minus the
amount of rework required to finish the amount of work that was thought
to be completed. The units of loss can be in units of energy (joules or electron volts), mass (commonly, kilograms or pounds), material wealth (converted into local currency, e.g., dollars), or information (bits as adopted by
Shannon for information (Shannon 1948)).
Engineering Systems Integration
maintenance, and service. According to Taguchi, after the product is put into
use, it is society and the customer who bear the cost for low quality. However,
we distinguish between the customer’s and society’s responsibilities in contrast to those attributable to the seller. Even while the seller’s purview can be
narrowed to the Taguchi limit by eliminating all interactions with the customer after the shipping event, our general perspective considers real costs
as well as the costs of negative customer reaction. Sellers sometimes have
difficulty in capturing and accounting for money and money-equivalencies
spent by customers to deal with problems, dissatisfaction, and inconvenience
associated with low quality. The approach here of developing and applying
a quality loss function allows quantitative evaluation of losses caused by
variations in behaviors and limits of performance specifications as they consociate with various functions of the product (Choi and Langford 2008).
Since Taguchi’s quality loss function is primarily focused on manufacturing, a more general formulation of loss functions is needed beyond his quadratic formulation to assist in analysis and decision making that must be made
during other lifecycle stages of the product, including conceptualization,
research, development, integration, operations, maintenance, and disposal.
The requirement is for a quality loss function that is applicable for the lifecycle of a product or service. Further, we must tackle head-on the definition
of product function and associated performance(s). Taguchi uses a quality
loss function to evaluate product performance relative to the performance
specification. When applying Taguchi methods, performance evaluation
becomes a most demanding task that challenges managers to distinguish
carefully between processes and functions, without providing the benefit
of firm definitions and theoretical standing. The diversity of definitions of
performance, the complexity of measuring performance, and the scarcity of
generally accepted performance measures compound these problems.
In general, there are at least seven distinct, although not necessarily mutually exclusive, performance measures used in practice. These are effectiveness, efficiency, quality, productivity, quality of work life, profitability, and
innovation. Thus, performance can be defined as a concept that takes on
different meanings in different situations for different organizational systems (Kaplan and Norton 1992, 1993, 1996; Kumpe and Bolwijn 1994). For
example, efficiency, quality, time, innovation, and contribution to profit are
often used as performance or effectiveness measures. Taguchi used quality
(i.e., loss) as a performance measure for evaluating product performance.
When referring to EMMI, performance can be defined as the net work
accomplished during a period t. For example, the net work accomplished
during a period t is equal to the amount of work “completed” minus the
amount of rework required to finish the amount of work that was thought
to be completed. The units of loss can be in units of energy (joules or electron volts), mass (commonly, kilograms or pounds), material wealth (converted into local currency, e.g., dollars), or information (bits as adopted by
Shannon for information (Shannon 1948)).