THE STRUCTURE OF PATENT AUTHORSHIP NETWORKS

IN JAPANESE MANUFACTURING COMPANIES

Kohei Tsuda, Frank J. Rinaldo, Victor V. Kryssanov, Ruck Thawonmas

Faculty of Information Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, Japan

Keywords: Patent, Inventorship networks, Power law.

Abstract: Technological and research strategies are becoming more significant as they create future value in the

market. The core of these strategies is the creation of patents, which help eliminate or contain competition.

Companies seek to learn the research strategies of their competitors. At the same time, all companies try to

hide their own strategies but they generally cannot, because patents have to be filed and therefore exposed at

a patent office and even made globally (e.g. via the WWW) accessible on-line. Part of the technological

strategy of a company can be determined by observing the patents it files, their timing and their authors.

There have been many studies about patents reported in the literature, with most of them focusing on the

connectivities existing in co-citation, co-patent networks. In the presented work, the focus is on the

inventors. Given the patent files of a company, one could possibly predict the company’s current and future

research and production strategies. Furthermore, if the inventors are known, the human resources of the

corresponding companies could naturally be scrutinized. The latter would allow to estimate the mechanism

prevailing

in the process of patent creation at a specific company. A novel approach to analyze the

professional activities of company inventors is proposed and applied to determine the inventive strategy of

Japanese manufacturing companies. The presented results can be used to optimize knowledge and recourse

management within a company.

1 INTRODUCTION

Technological strategies are becoming more

significant as they create future value in the market

(Probert and Shehabuddeen, 1999; Burgelman et al.,

2003). The core of these strategies is the creation of

patents that helps eliminate or contain competition.

Companies also need to learn the patent strategies of

their competitors (Rivette and Kline, 2000).

At the same time, all companies need to hide

their own technological strategies but cannot,

because patents have to be published at a patent

office as quickly as possible. As a result, part of the

technological strategy of a company can be

determined by observing the patents it files, their

timing and their authors.

There have been many studies reported in the

literature about patent/authorship networks. Most of

them deal with the structure of the authorship and

focus on the patent system and its surroundings.

There are studies that explore the grouping of

patents through a bibliographic coupling analysis

(Huang et al., 2003) and the linking of science and

technology as revealed with bibliographic references

(Verbeek et al., 2002). A recent study suggests that

there are two mechanisms of patent diffusion:

geographic localization of knowledge flows and

concentration of knowledge flows within company

boundaries (Singh, 2005). Many works described

knowledge diffusion and flow by using complex

network theory (Chen and Hicks, 2004); target areas

included industries (Meyer, 2001), universities (Jaffe

and Trajtenberg, 1996), and global enterprises

(Tijssen, 2001).

Much of the current research is therefore about

patent citations, yet as a rule it targets multinational

corporations (Verspagen, 2000; Bhattacharya and

Meyer, 2003). Researchers tend to focus on the

structure of patent co-citation and generally on

patent networks (Mogee and Kolar, 1999). These

studies analyze knowledge diffusion through patent

citation, but there are few studies that attempt to

utilize these analyses to improve the efficiency of

patent creation process. There is little information

available on the management mechanism to create

patents effectively and on inventor networks.

289

Tsuda K., J. Rinaldo F., V. Kryssanov V. and Thawonmas R. (2006).

THE STRUCTURE OF PATENT AUTHORSHIP NETWORKS IN JAPANESE MANUFACTURING COMPANIES.

In Proceedings of the International Conference on e-Business, pages 289-293

DOI: 10.5220/0001427102890293

 SciTePress

The purpose of this work is to explore the

mechanisms responsible for the creation of patents at

different manufacturing companies. A model of

these mechanisms is proposed and used to analyze

the professional activities of company inventors

using patent authorship data.

Figure 1 provides a conceptual view used in the

presented study. The patent data is taken from the

Japanese Patent Authorship Network; it includes

7,396 inventors filing 9,349 patent applications. In

Section 2, characteristics of the patents, the

inventors, and their social network are discussed. In

Section 3, a sketch of the system-theoretic analytic

framework used in this study is given, and Section 4

presents a case study. Finally, Section 5 discusses

characteristics of the patent creation process and

Section 6 gives concluding remarks and outlines

directions for future research.

2 PATENTS AND INVENTORS

Patents are created by inventors, and their authorship

is similar to that of academic papers. One might

assume that the academic authorship analysis might

be used to investigate the process of patent creation

(Liu et al., 2005).

The above analogy does not however work.

Patents as a rule have a strategic (and financial)

significance, while academic papers do not, and the

academic citation studies are not readily applicable

for inventor network.

Inventors are usually researchers at companies

with R&D sections. While there are many individual

inventors in the US, in Japan almost all inventors

(and their patents) are affiliated with companies.

What is an inventorship network? It is the list of

researchers and their inventions, and their

corroborative efforts. It reflects the professional

relationships that exist between the authors in the

process of working on a patent. Invention activities

assume communication and exchange of ideas, and

if there are co-authors (co-inventors), there is

usually a strong connection between them as

indicated by the patent (authorship) network. If such

collaborating individuals are co-authors on more

than one patent, the corresponding professional

connection is even stronger.

Who would be considered as the most important

person in a company’s R&D? Probably the person

who has the greatest number of patents; this may

however not necessarily be so. In Japan, it has been

the case for a researcher’s superiors to be included

as a patent author. This could distort who might be

the most important person as a high level manager

could have his name on many patents with very little

contribution. People having a number of registered

patents are probably important, but the truly

essential person is the one who is the most “truly”

influential to other researchers.

3 THE ANALYTIC APPROACH

A complete (whatever it would mean in the given

context) theory of social interactions requires a

theoretical understanding of statistical regularities

observed in or simply associated with the social

system under examination. The most often cited

(and overwhelmingly best studied) approach to the

study of various networks having a social origin is

Zipf’s “principle of least effort” (cumulative

advantage, preferential attachment, etc), yet

sometimes presented as simply the power law. The

latter law states that the frequency of a link (contact,

citation, authorship, etc.) decays as a power function

of its rank (Newman, 2005). It should be noted

however, that despite the apparent relevance and

proven universality of this law, it can be obtained

from a variety of mechanisms (Mitzenmacher, 2003)

and by itself, it does not provide insights about the

organization of the social system, the system’s

dynamics and evolution.

In an attempt to establish a theoretical basis for

the investigation of inventorship networks, the

presented study exploits the analytic framework

originally proposed by the authors of Reference

Figure 1: The concept of the study: focusing o

communication networks of inventors.

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290

(Kryssanov et al., 2005). The framework deals with

the observed behavior of a complex system (e.g.

social, economic, biological, etc.), and it allows for

the evaluation of the internal, “hidden” structure and

dynamics of the system, based on estimated

parameters of the observed stochastic process (i.e.

the system’s behavior as registered).

Specifically, to explore the mechanisms of patent

generation, the following model characterizing the

dynamics and structure of the social network in

focus has been used (also see Kryssanov et al.,

2006):

...,2,1,

)()1(

)(

⎟

⎠

⎞

⎜

⎝

⎛

−

+−

∑

ckP

(1)

where parameters

0>b , 0>

, and )(kP is the

probability mass function of the occurrence (count)

of the network’s observed state change.

It should be emphasized that the well-studied

form of the power law

/)(

νν

kbkP (Pareto 1

distribution) is a particular case of the more general

distribution (1) when the investigated system is

homogeneous (i.e. when

). In the latter case,

an “equivalent” of the Zipf’s law for the rank

statistics can be written as

1/1/11 −−+−

−= lbrlbf

νν

where

f is the relative occurrence frequency of the

r-th popular unit. While the rank-frequency form is,

perhaps, most often used in the studies of patent and

article authorship- networks, we will employ the

general form (1) to explore the dynamics and

structure of inventorship networks in Japanese

manufacturing companies. The observed property

(as represented by the stochastic variable

k ) is, in

this case, the number of patents filed by an

individual. It will thus be assumed that filing

(registering) a patent indicates a change in the

internal dynamics of the corresponding social

system.

4 INVENTORSHIP NETWORKS

Data used in the following analysis is a sample

representing the number of patents applications filed

for 7,396 inventors (totally 9,349 applications) using

specific IPC (International Patent Classification at

WIPO - World Intellectual Property Organization)

categories about micromachining-techniques (Table

1) in Japan during 1988-2003. In this section, an

analysis of the specific sub-set (the IPC categories)

of the data is done, and its results are used to detect

the structure of the patent creation process.

Figure 2 shows the results of modeling the patent

authorship with 2-component and 3-component

models from the previous section (i.e. for M = 2 and

3, respectively). A traditional model would suggest

only 1 component represented by a single straight

line in the double-logarithmic chart, which is

obviously not the case for this data. In the analysis,

the 2-component model appears to be a better

Figure 2: Results of the modeling of the Japanese

companies’ patent network.

/1 is an estimate of the

average number of patents per author;

bvE /)( =

Section Class Subclass Description

B 81 All

MICRO-STRUCTURAL DEVICES OR

SYSTEMS

82 NANO-TECHNOLOGY

H 02 N

ELECTRIC MACHINES NOT OTHERWISE

PROVIDED FOR

Table 1: IPC categories used for sampling.

THE STRUCTURE OF PATENT AUTHORSHIP NETWORKS IN JAPANESE MANUFACTURING COMPANIES

291

choice, based on the parsimony principle ("the best

is the simplest model"), since the AIC difference –

Akaike’s Information Criterion assesses the relative

Kullback-Leibler distance between the fitted model

and the unknown true mechanism, which actually

generated the observed data (Akaike, 1983) – is not

too large (models may be considered equivalent or at

least close when

2AIC ≤Δ (Sakamoto et al.,

1986)). Both models, however, suggest that there are

two subsystems, "static" (~20%) and "dynamic"

(~80%), in the social network investigated. The

static system appears to be due to basic study

activities in the R&D (or “pure” research) section of

a company, while the dynamic system due to

innovation activities in the mass production process

(incremental improvements, etc.).

It is thus proposed that the static system is based

on (or is made up of) “basic” or “pure” research.

This would be research without a very specific

(focused) goal. The dynamic system, on the other

hand, could be based on the Japanese idea of

incremental improvements. This is research (in a

very specific area and, usually, with a very specific

goal) to improve an already manufactured product or

product design. Figure 3 provides a conceptual

image of the two systems to create patents.

5 PATENT CREATION

PROCESSES

Almost all patents discussed above were created by

collaboration of inventors. Regarding the patent

categories used in this study, Japanese companies

have competitive power in the field of

micromachining technique, but do not have it in the

IT and the biotechnology areas. In addition, as it

follows from the previous analysis, almost all of the

patents are created in the dynamic system. In other

words, it appears plausible that, in Japanese firms,

R&D departments (“pure research”) do not play a

major role in the creation of patents.

The previous studies about effective team work

suggested that the decisions of team members are

important for the success of a project (Bixby, 1987),

and referred to factors needed for creative teams, but

did not mention the team dynamics.

Japanese manufactures are involved in training

processes for innovation, especially focusing on the

importance of “Kaizen” (Imai, 1987; Lillrank and

Kano, 1990). It is perhaps this culture that caused

the observed dynamics in the inventorship networks.

Possible reasons for why the contribution of the

innovative activities in the patent creation process is

more significant are as follows. If every patent

application is valuable, the product development

processes prevails over the basic study activities. If,

however, the product development has the same

impact (priority, etc.) as the basic study activities,

then one patent in basic studies is more “powerful”

(in terms of the patent authorship, as revealed

through the social connections and count of filed

patents) than one in product development. Otherwise,

the product development processes may naturally

result in more patents than the basic study activities.

It has been found through interviews that the

presented study findings confirm the general

intuition of the respective companies’ managers

about the structure and the dynamics of the inventive

activities.

6 CONCLUDING REMARKS

The analysis in the previous section has shown that

there are two possible mechanisms of patent creation

in Japanese manufacturing companies. The less

(observationally) influential mechanism tends to be

focused on genuinely new products and new ideas.

Traditionally the later has a higher risk (e.g. due to

low return on investment), as large jumps in

technology may not be financially justifiable. In

contrast, the more influential mechanism is

associated with activities focused on current

products and ideas with the goal of enhancing or

improving on them. This type of patent creation

activities obviously has a better financial

justification, as there is more knowledge about the

Figure 3: The concept of the patent creation.

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current product and its profitability. Hence, the

cost/reward ratio for the incremental patent research

makes it easier to justify.

Currently, the process to create patents is often

highly inefficient and very costly in Japan; the

emphasis on process innovation should be shifted to

product innovation in Japanese firms since, in fact,

R&D budgets have been recently increasing without

producing economic results (OECD, 2001). If

‘process’ innovation is driven by the dynamic

mechanism, the companies need to change the

management system to reduce dynamics in the

inventor networks.

In a future study, we will focus on the details of

inventorship networks, particularly on the inventors

and their (apparent) areas of expertise. This more

detailed analysis might suggest ways for a company

to increase its synergy between inventors to more

quickly develop patents.

Japanese working culture is changing

dramatically, and recently it is not enough to focus

solely on the organization of a company to grasp its

potential. The importance of individual inventors

and their connectivity should further be analyzed

because they are the source of the patents that

largely determine technological strategies.

There are also plans to conduct a similar analysis

of other countries’ patent data (e.g. the US and the

EU) to determine if the patent creation mechanisms

within a company environment differ from country

to country.

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