QFD by TRIZ

First presented at TRIZCON2001, The Altshuller Institute, March, 2001

Michael Schlueter
Philips Semiconductors
Stresemannallee 101, D-22529 Hamburg GERMANY
Phone: +49 40 5613 3423; Fax: +49 40 5613 3392
Email: Michael.Schlueter@philips.com

Understanding the real needs of the customer is the central concern of Quality Function Deployment (QFD). This paper investigates, how TRIZ could be used to introduce structure into customer requirements. It relates TRIZ concepts, like absent or available useful functions, harmful functions and ideality, to the Kano model as given in Cohen’s book [1]. It gives a guideline how to identify Kano’s 3 levels of qualities from TRIZ analysis of the customer’s situation.

“I can’t sell my product successfully, when it does not satisfy my customer. How to do that effectively?”

These simple words summarize the motivations for companies to take the struggle of QFD. The QFD community continuously publishes success stories, how mediocre products are converted into competitive products systematically. According to QFD-practitioners cycle times can be reduced, customers can become happier with the products and market shares can be increased.

Cohen reports many practical problems, which QFD-teams encounter in reality to obtain customer focuses [1]. TRIZ provides means to describe and structure complicated situations. TRIZ also provides ways to improve a difficult situation. This paper investigates how TRIZ could be used to improve the quality of QFD-input without changing QFD.

QFD-teams compile and structure customer requirements for products and services. Functionality of existing products is compared and benchmarked from a customer’s perspective. Successful QFD-teams manage to separate customer requirements completely from specific technical solutions. They map the complex relationships between requirements and various design aspects in QFD-matrices.

This process improves understanding of success factors and documents customer oriented market research. It can create very concise and comprehensive information, which can help to continuously decide in favor of the customer throughout design, manufacturing and sales.

Bob King has compiled a plethora of QFD-matrices used [2]. It depends on the situation which matrix is the best to start with. The most frequently used QFD-matrix is the A1-matrix, which maps “customer demands” with “quality characteristics of the product”. It has become famous as “the house of quality” due to its graphical representation.

To the author’s experience it can be easier to start with the A2-matrix, which maps “product-functions” with “quality characteristics of the product”. It seems to be easier to talk about what products shall or shall not do. Once clustered the functional requirements (rows) can establish an appropriate metrics of “required quality characteristics of the product” (columns). Using this metrics as input (columns) for the A1-matrix can help to identify relevant “customer requirements” (rows) more easily. Starting with the A2-matrix allows also engaging TRIZniks who are strong in analyzing functions of a system.

Before entering information into QFD-matrices the information must be structured to avoid excessive growth of a QFD-matrix. Bob King provides many techniques, which are widely used today [2]. Glenn Mazur proposes “Voice of Customer Analysis” to structure the process of gaining relevant knowledge on the customer’s real needs [3].

Glenn Mazur emphases to focus on customer, not on the product. He states:

Nothing Wrong ¹ Anything Right [3]

to indicate the inherent short comings of many design processes. A product that does not perform wrong is not necessarily a product that is “right for the customer”. Absence of failures is no guarantee for success in the market place.

He suggests that a supplier should go to the gemba , just like Japanese companies do. “Gem” means “current, present”, “Ba” means “location or place”. Gemba is the true source of information. It is the place and time, where the product is actually used by the customer and creates value for the customer [3].

In brief, he suggests to “walk a mile with the customer” and to observe what he/she is doing with the product, what kind of problems occur, what he/she says and not says. While visiting the gemba the main objective of the supplier should be to perceive the unspoken. Evaluating and structuring these observations gives the supplier the opportunity to identify expressed and hidden needs for different customer-groups.

Customer requirements can be invisible to both the customer and the supplier. Noriaki Kano proposed using a simple model to better understand customer needs. He compares the degree of fulfillment of requirements by the supplier with the degree of satisfaction by the customer. It is very useful to keep this model in mind when visiting the gemba.

Kano distinguishes 3 categories of customer requirements (Figure 1) [1, 4]:

• Expected requirements are “self-evident” and unspoken. E.g. one can expect that a car will drive and can stop. Even a 100% fulfillment of these aspects will never satisfy a customer. On the contrary, when these requirements are absent or exhibit a failure, customers will be dissatisfied. Kano calls them dissatisfiers.
• Revealed requirements are expressed in one way or the other. They are not hidden. The degree of fulfillment is highly correlated with customer satisfaction, like asking for a specific interior of a car. Kano calls them satisfiers.
• Exciting requirements are not expected and are not asked for. However, should they be available by the product, customer can become very excited, like having a GPS-system in a standard car at no extra cost. Kano calls them delighters.

What may be exciting for one customer may be an expected quality for another. What a customer wants to achieve by using the product can deviate significantly from the design intention of the product. A customer-oriented formulation of product functions needs to be worked out.

The primary useful function (PUF) of a woolen facemask is to protect (skin against cold weather conditions). A motorcyclist desires to wear a facemask during cold seasons. The supplier of the facemask can improve the PUF to protect by providing a better thermal insulation. The facemask keeps the face of the motorcyclist warmer, who may be delighted.

A bank robber may be very dissatisfied with a high-thermal-insulating facemask. During robbery in a warm bank the robber may need to lift the mask, showing his/her face. The bank robber needs another PUF: to hide (face).

The facemask provides both properties to protect AND to hide. The same product can have several different primary useful functions depending on the different objectives of different customers. Knowing about the objectives of a specific group of customers is important to identify the correct PUF and to improve the right product functions by QFD or TRIZ.

Chapter 2.8 of reference [1] provides many interesting details on Kano’s qualities.

“Dissatisfiers are the absence of ‘expected quality’, in the sense that customers expect products to be essentially flawless, and if they are not, the customers are dissatisfied. Examples of dissatisfiers are scratches or blemishes on the surface of a product, broken parts, missing instruction booklets, or missing features that are routinely supplied in similar products. Customers don’t tell us they want ‘expected quality’ because they take for granted we will provide it.”

From a TRIZ-perspective Cohen talks about:

• missing Useful Action
• available Harmful Action

A “QFD by TRIZ”-process should reveal the primary useful functions of a product, from a customer’s perspective. By applying TRIZ-functional models the situation can be significantly clarified, as indicated in later chapters of this paper. Very powerful tools to reveal Harmful Actions are the sabotage- [5] or the more refined AFD-technique [6].

“A satisfier is something that customers want in their products, and usually ask for. The more we provide a satisfier, the happier customers will be. (…) Examples of satisfiers are increased capacity, lower cost, higher reliability (…) In other words, you can expect the satisfiers to be present in all the competitive products, to a greater or lesser extent.”

Very clearly from a TRIZ-perspective Cohen talks about:

• available Useful Action

“Delighters are product attributes or features that are pleasant surprises to customers when they first encounter them. (…) A typical customer reaction to a delighter is to say to a friend, ‘Hey, take a look at this!’

(…) The 3M Post-it Note is another example of a delighter. It’s a product that filled user needs that had not been filled satisfactorily.

(…) The needs that delighters fill are often called ‘latent’ or ‘hidden’ needs (…) These needs are sometimes intimately linked to customer’s perceptions of the limits of technology (…)”

From TRIZ-perspective delighters seem to be related to:

• insufficient Useful Action
• limitations = trade-offs = physical conflicts

Overall, eliminating dissatisfiers (introducing sufficient Useful Action, eliminating Harmful Action), strengthening satisfiers and introducing delighters (introducing sufficient Useful Action, eliminating conflicts) will increase the Ideality of a product or service.

The author’s perception of the situation is summarized in the Table 1. As will be shown later, Dissatisfiers and Delighters differ by their impact on customer’s value (cf. Figure 2).

There is a partial overlap to Steve Ungvari’s paper [7]. During the recherché phase for this paper the author found an interesting paper from Ellen Domb, which also compares QFD and TRIZ [8]. She indicates, for example:

• Functional- and Resource Analysis, as known from TRIZ, are important for QFD
• TRIZ can be used to identify and resolve conflicts during analysis of the “Voice of the Customer”
• Visiting the Gemba is a good chance to understanding contradictions and use of resources.

For practical purposes Table 1 can be used to identify Kano’s qualities in a more objective way:

• Identify objectives of your customer
• Understand the role of your product for your customer
• Understand how your product impacts your customer’s Perceived Ideality
• Model the Gemba of your customer (UA, HA)
• Identify dissatisfiers, satisfiers, delighters, hidden needs with Table 1

According to TRIZ the Ideality of a product will increase inevitably during the evolution of the product.

Many products have been designed for a dedicated purpose. For example a car is designed to drive, a printer is designed to print or a computer is designed to compute. The product’s name itself already indicates a specific, obvious primary useful function. Improving these obvious functions leads to an increase in Obvious Ideality.

When planning and deploying a product in a customer oriented way we have to account for perceived functions of the product. Improving these will increase the Perceived Ideality of the product. Perceived Ideality will be different for different customers. Perceived Ideality can deviate significantly from Obvious Ideality.

Why does a customer use a specific product?

Initially the customer has a specific objective in mind. The customer selects a product, which provides a function to achieve the objective. Achieving the objective creates a specific value for the customer, which is very satisfying.

A TRIZ- model of Useful and Harmful Functions of a product should at least indicate 3 types of actions, so that Kano’s qualities can be identified via Table 1:

• Product functions from the customer’s perspective (useful, harmful, insufficient, conflicting)
• Customer’s objective(s) (expected, unexpected)
• Value created for the customer (expected, unexpected)

It should reveal the mechanisms of value creation for the customer. Further resources and fields available to the customer can be included, which helps to understand the observations made at the gemba.

The Problem Formulator of Ideation’s software “IWB2000” [9] is used to show the minimum cause-effect relationships required identifying Kano’s qualities (Figure 2). (Green) Boxes indicate useful functions, while (red) boxes with rounded corners indicate harmful actions. Arrows indicate a “produce” effect, while crossed arrows indicate a “counteract” effect.

A functional model of the customer’s situation should look similar to Figure 2 and should allow applying Table 1.

The author assumes that the creation of expected value results in satisfaction of the customer, while the creation of unexpected value leads the customer to being delighted. The harmful actions, indicated in Figure 2, counteract achieving the customer’s objectives. As a result the customer will be dissatisfied.

In reality a delighting function will also be subjected to dissatisfiers or hidden needs. It looks like Kano’s delighters are strongly related to what the customer thinks is feasible.

In the previous chapters the author showed, how the customer’s situation could be modeled by TRIZ from a QFD-perspective. We now can go one step further and investigate, how the Kano-situation could be improved.

Activating the Diagram/Formulate-menu of the IWB2000 gives 11 directions of innovation for the model in Figure 2:

#1. Find an alternative way to obtain [the] (achieve objective) that offers the following: provides or enhances [the] (create expected value), does not require [the] (use an expected UA /satisfier/), is not influenced by [the] (encounter a HA /dissatisfier/), (encounter a missing UA /dissatisfier/) and (encounter limiting conflicts /hidden need/).

#2. Find an alternative way to obtain [the] (create expected value) that does not require [the] (achieve objective).

#3. Consider transitioning to the next generation of the system that will provide [the] (create expected value) in a more effective way and/or will be free of existing problems.

#4. Find an alternative way to obtain [the] (use an expected UA /satisfier/) that provides or enhances [the] (achieve objective).

#5. Find a way to eliminate, reduce, or prevent [the] (encounter a HA /dissatisfier/).

#6. Find a way to eliminate, reduce, or prevent [the] (encounter a missing UA /dissatisfier/).

#7. Find an alternative way to obtain [the] (achieve more than expected) that offers the following: provides or enhances [the] (create unexpected value), does not require [the] (use a sufficient or insufficient UA /delighter/).

#8. Find an alternative way to obtain [the] (use a sufficient or insufficient UA /delighter/) that provides or enhances [the] (achieve more than expected).

#9. Find a way to eliminate, reduce, or prevent [the] (encounter limiting conflicts /hidden need/).

#10. Find an alternative way to obtain [the] (create unexpected value) that does not require [the] (achieve more than expected).

#11. Consider transitioning to the next generation of the system that will provide [the] (create unexpected value) in a more effective way and/or will be free of existing problems.

Successful QFD-teams may know many of these proposed strategies. These proposals can be used to choose an appropriate starting point for a QFD. Proposal #2, #3, #7, #10, #11 focus on value creation regardless of the product. The may be interesting for highly innovative market strategies. A semi-hypothetical case study will elucidate these options.

This simplified example illustrates the difference between improving the Obvious Ideality of the product and the Perceived Ideality by a customer. A few hypothetical scenarios are given to illustrate how TRIZ can be used to improve customer orientation.

Over the last 15 years the author used different generations of desktop printers. This example is used to better understand the development of QFD-requirements in time.

• When starting at Philips Semiconductors the LA50 printer was widely used. In the beginning it was used as a shared printer. When these printers were replaced by laser printers they occasionally served as office printer.
• In the beginning 90’s the author bought a private high quality printer NEC 24P. At that time he needed printouts from source codes frequently. He wanted to use a low-noise device so that his little sun could continue to sleep.
• In the mid 90’s he upgraded to a LED-printer from Panasonic, which was faster, less noisy and had a much better image quality.
• In the late 90’s hp’s Inkjet was introduced. The author finally used it as a trade-off solution with respect to the harmful effects from the LED-printer.

Perceived properties of these printer by the author over time:

LA50 (9 needles)	very loud L, very slow L, very bad printout L, free J
NEC 24P (24 needles)	quite fast J, more silent J, expensive L
Panasonic (LED)	very fast J, very good image J, silent J, ozone L, price L
Hp-Inkjet (ink)	slower L, worse image quality L, color J, moderate price J, no ozone J, no odor J

The author’s perception of the changes in quality of the printers can be visualized by a simplified estimate of the printer’s Perceived Ideality (Figure 3) as derived from Table 2.

In Table 2 the number of satisfiers is compared with the number of dissatisfiers. Subsequent printers relatively improve useful functions and relatively worsen harmful functions.

This simplified estimate fits with the authors overall impression of the different printers, more or less.

Kano’s 3 different qualities can also be followed in this example:

1. In the era of the LA50 the author hardly could imagine that at one day the image quality of printouts might become excellent (initial situation).

2. A better quality of the printout was one selection criterion for buying the NEC24P (expected satisfier).

3. When the Panasonic printer became available, the low noise level was exciting (unexpected delighter). The production of ozone, resulting in bad air conditions, was not expected and not demanded (unexpected dissatisfier).

4. In the era of the Inkjet a good printout quality and low noise had become taken for granted (expected satisfiers).

When being asked to improve his/her printer, a supplier may focus on the obvious thing to do: improve the printer itself. While this might happen inevitably in the evolution of the printer, it may not be exactly what the customer wants.

There are many ways to utilize TRIZ for this purpose. A free-style TRIZ approach is sketched here. The supplier can formulate the primary useful function (PUF) of the printer. Next, he/she can envision the Ideal Printer and find an approximating device, which may be build:

The exact Obvious-Ideal-Printer may be difficult to envision. An approximation of this Obvious-Ideal-Printer (no bulky printer, just its output) can become a reality today. IBM and MIT recently announced prototypes of the e-book, where sheets of electronic paper are bundled into a book [10, 11].

The desired e-paper might be based on this concept. Instead of passing paper through a printer, a pile of e-paper could be modified by electronic data, forming a pile of persistent, individual printouts. The ‘printed’ pile of e-paper could than be used and handled exactly like ordinary paper (e.g. punching, binding, writing notes on it).

When the supplier wants to understand the mechanisms of dissatisfiers AFD may be a valuable TRIZ-tool to apply for this purpose:

How to deteriorate the PUF? -> AFD-analysis -> it is important to understand the mechanism of the PUF and how to deteriorate it by the available resources.

In order to produce the printout the e-paper must be modified in some way. In order to provide interaction with electronic data a receiver must receive data from an appropriate data-channel and must pass it to the e-paper in a suitable internal format.

TOP-analysis from Zinovy Royzen is used to derive a simplified functional model [12].

Receiver	à data	=> data_received	receive-function (auxiliary function)
data_received	à e-paper	=> e-paper_modified	print-function (PUF)
(Read: a receiver acts usefully on data. As a useful result, data are received.)
(Read: data_received act usefully on e-paper. As a useful result, e-paper is modified.)

Dissatifiers could be created by disturbing the PUF, e.g.

• prevent receiving data (how to do that?)
• prevent printing (how to do that?)

and by creating any other kinds of failure, e.g.:

• low durability
• high cost.

The supplier might formulate a business plan from these considerations, start development and, later on, sales. The self-printing e-paper will certainly be a very innovative product, which will find its market. However, this product might not create the best value for the customer.

The author assumes he represents a reasonable market-segment of programmers in this example. A detailed market research activity might have revealed the following situation, why this printer creates value for these customers (Figure 4).

The reason to use the printer is to develop a „functional program with less bugs“, which is a value for this customer. The customer expects to achieve this result by frequently reviews of printouts. Because printing turned out to occur at low noise, printouts can be created at any day time. This allows to start more complex projects, which fits the long term perspective of this customer in this market-segment. However, unexpected emission of ozone limit these capabilities.

The supplier can initiate 3 types of QFD’s in order to capture the „voice of the customer“:

• QFD based on product functions
• QFD based on customer’s objective
• QFD based on customer’s value

The A1-matrix could look like Table 3. The left part of Figure 4 is utilized as customer requirements.

This matrix reflects the customer demand (left), relevant measurement characteristics (top), global interaction between these (symbols) and relevance to the customer (right). The weighted importance (bottom) can help the development team to spend their development resources in a way which will guarantee meeting relevant customer objectives. In this example it would be important to focus on improvement in speed first and noise levels next.

It is interesting to note that TRIZ can go one step further here. The IWB2000 suggests 3 directions to improve the functions of the printer functions:

1. Find an alternative way to obtain [the] (faster, high quality printing /satisfier/) that provides or enhances [the] (review source code).
2. Find a way to eliminate, reduce, or prevent [the] (emit ozone /dissatisfier/).
3. Find an alternative way to obtain [the] (low noise printing /delighter/) that provides or enhances [the] (start more complex projects).

The objectives of the customer are included in proposal #1 and #3. Thus they could be included as further quality characteristics in column „other characteristics“ or as design alternatives in QFD-matrix E1 (Pugh concept selection [2]).

The middle part of Figure 4 is utilized now as customer requirements (Table 4). Customer demands are different now and the quality characteristics have been adapted. Further considerations are the same as made for Table 3. Some quality characteristics from the previous QFD might still be useful, like „Printer speed“.

The directions of innovation now give non-product related proposals, which may be hard to implement by the printer itself:

1. Find an alternative way to obtain [the] (review source code) that offers the following: provides or enhances [the] (functional program with less bugs), does not require [the] (faster, high quality printing /satisfier/), is not influenced by [the] (emit ozone /dissatisfier/).
2. Find an alternative way to obtain [the] (start more complex projects) that offers the following: provides or enhances [the] (create program with high functionality), does not require [the] (low noise printing /delighter/), is not influenced by [the] (emit ozone /dissatisfier/).

Instead these proposals can guide the supplier to consider entering the completely different market of software engineering or to supply the printer with additional benefits. For example, the supplier could provide a booklet with the printer, how to avoid bugs while concepting and writing programs. The booklet might help the customer reducing the need to print out frequently for check purposes. Being a design alterntive such ideas will probably be handled by QFD matrix E1 (Pugh concept selection [2]).

Finally, the supplier might even decide to take a completely different route and support the customer to achieve its ultimate values:

1. Consider transitioning to the next generation of the system that will provide [the] (functional program with less bugs) in a more effective way and/or will be free of existing problems.
2. Find an alternative way to obtain [the] (functional program with less bugs) that does not require [the] (review source code).
3. Consider transitioning to the next generation of the system that will provide [the] (create program with high functionality) in a more effective way and/or will be free of existing problems.
4. Find an alternative way to obtain [the] (create program with high functionality) that does not require [the] (start more complex projects).

The right part of Figure 4 is utilized now as customer requirements (Table 5). Characteristics from the previous QFD’s may appear here as well, like „Printer speed“ and „Review frequency“. However, due to the different directions aimed at they will probably end up with a very low weighted importance rating. This would be a typical QFD-result and these aspects will probably be excluded from further considerations.

In reality the author made a decision, which matches the QFD based on customer’s values. He switched from a Windows-based software development environment, which required using a very inconvenient, complex and hard-to-understand library, to a Linux based software environment with Perl and Perl/Tk. His development rate of complex programs increased considerably, demanding for less individual printouts.

• Improving the product focussed Obvious Ideality can result in a highly innovative product of a very good quality level. However, there is a chance to miss the market.
• Focussing on improving Perceived Ideality of a specific customer group can provide competitive advantages.
• A QFD based on product functions will create QFD’s which are known in literature. Results can be similar to the “Obvious Ideality”-case.
• A QFD based on customer’s objectives may allow incorporating other interesting aspects, which are relevant to the customer. They are simply related to using the product.
• A QFD based on customer’s values can provide the supplier with a new strategic perspective.
• It may be interesting for a supplier to combine these 3 types of QFD’s when deriving competitive roadmaps for the product.

Visiting the gemba will probably still be necessary today, as Glenn Mazur proposes [3]. It may be the only means to begin understanding the customer’s needs. In TRIZ terms visiting the gemba will reveal fields and resources available to the customer and hidden to the supplier.

It will be interesting to investigate to which degree an

• ACO (Anticipating Customer’s Objectives) and
• ACV (Anticipating Customer’s Values)

methodology can be established. AFD, as known within the TRIZ-community, may be suited as a starting point for this purpose.

AFD allows predicting failures of a system. A main step in this process is to reveal all flows within the system because it has been found that failures tend to occur at high concentrations of flows:

• Flow of energy
• Flow of information
• Flow of substances.

Then it is investigated, which degrees of freedom are available within the system to create failures (= unwanted results) [6].

In the facemask example above we encounter a similar situation. It is interesting to understand how the product can be used for different purposes. Different customers utilize different properties of the product, facemask. More precisely, they utilize different flows, e.g.:

• Flow of heat (motor cyclist)
• Flow of light (bank robber)

These flows could be generalized to identify potential market segments for the product. E.g. the heat flow related market segment could also include joggers, skywalks, mountain climbers etc. The light flow related market segment could also include swat teams, theater groups etc. However, following these routes will lead to increasing Obvious Ideality, only. Objectives and values remain hidden.

Products, increasing the Obvious Idealities, might be:

• Transparent, heating facemasks
• Absorbing, cooling facemasks

More investigations will be necessary to derive truly ACO- or ACV-methods, which allow improving Perceived Idealities. These methods should make visiting the gemba completely obsolete, while allowing to achieve the same or a better QFD-result.

Modeling different aspects of QFD by TRIZ models was an interesting experience in itself.

TRIZ can be used to introduce structure into customer requirements. When the mechanism of value creation for the customer is modeled by TRIZ it becomes possible to derive Kano’s satisfiers, dissatisfiers and delighters. The TRIZ model of this mechanism can be used to create 3 different kinds of QFD’s:

• QFD’s based on product functions
• QFD’s based on customer’s objectives
• QFD’s based on customer’s values

in a systematic way. They indicate very interesting marketing strategies.

The author finds it more accurate to replace the TRIZ term “Ideality” by the terms “Obvious Ideality” and “Perceived Ideality” in a QFD context.

It should be further investigated if a method to anticipate customer’s objectives (ACO) and a method to anticipate customer’s values (ACV) could be developed by TRIZ.

Michael Schlueter graduated in low-energy solid-state physics in 1987 at the Christian-Albrechts-Universitaet, Kiel. He visited CERN in 1984 as a summer student and other high energy physics facilities to witness front-end research. He started at Philips Semiconductors, Hamburg in 1986 and held various support-related positions for IC-development. Very early he started evaluating methods for quality improvement. He began with TRIZ in 1996, after following a presentation of Zinovy Royzen at the Taguchi Symposium in Los Angeles. He tried many contemporary approaches to TRIZ and is an active promoter of TRIZ within Philips.

[1] “Quality Function Deployment. How to make QFD work for you”, Lou Cohen, Addison Wesley Longman, Inc. 1995, ISBN 0-201-63330-2

[2] “Better Design in Half the Time”, Bob King 1989, ISBN-1-879364-01-8

[3] “Voice of Customer Analysis: A Modern System of Front-End QFD Tools, With Case Studies”, Glenn Mazur 1996, http://www.personal.engin.umich.edu/~gmazur/works/voice_of_customer.pdf

[4] “Voice of Customer Analysis”, Glenn Mazur 2001,

http://www-personal.engin.umich.edu/~gmazur/tqm/overheads/voc.pdf

[5] Alla Zusman, Ideation International, private communication Nov. 2000

[6] Dana Clarke, Ideation International, private communication Dec. 2000

[7] “TRIZ Within the Context of The Kano Model”, Steve Ungvari 1999, http://www.triz-journal.com/archives/1999/10/e/index.htm

[8] “QFD and TIPS/TRIZ”, Ellen Domb 1998, http://www.triz-journal.com/archives/1998/06/c/index.htm

[9] “Innovative WorkBench”, Software provided by Ideation International, http://www.ideationtriz.com

[10] “Digital Ink”, by Charles Platt, Wired May 1997

[11] “Ink for electronic paper”, by Barrett Cominskey et.al. , Nature Vol. 394, 16 July 1998

[12] TRIZ Workshop, Zinovy Royzen, Philips Semiconductors Hamburg, 1999

QFD: Quality Function Deployment
TRIZ: Theory to Resolve Inventive Problems (translated from a Russian acronym)
UA: Useful Action, same as Useful Function
HA: Harmful Action, same as Harmful Function
AFD: Anticipatory Failure Determination
DE: Directed Evolution
PUF: Primary Useful Function
TOP: Tool - Object - Product

Symbols are used in QFD to indicate strong, average and weak relationships between rows and columns. Each symbol is associated with a rating value. Most frequently symbols and ratings are chosen as:

¤ strong relationship, rating *9
¡ average relationship, rating *3
D weak relationship, rating *1

Customer’s importance ratings are usually indicated on a scale from 1 (not important) to 5 (very important).

An overall weighted-importance is calculated for the quality characteristics, which accounts for the importance of customer requirements and the relationships between needs and technical characteristics. E.g. “printer speed” yields 58 as weighted-importance in the example:

9*5 + 3*3 + 1*4 = 58