Software Product Line Evolution Method Based on Kaizen Approach Mari Inoki Toshiba Solutions Corporation1 and Waseda University 13-22 Katamachi, Fuchu-shi, Tokyo 183-8512, Japan +81 42 340 6357 [email protected] Yoshiaki Fukazawa School of Science and Engineering Waseda University 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, JAPAN +81 3 5286 3345 [email protected] ABSTRACT Continuing optimal product line development needs to evolve core assets in response to market, technology or organization changes. In this paper, we propose a product line evolution method based on the kaizen approach. Kaizen is a continuous improvement method that is adopted in Japanese industry. The important points of the kaizen are to prepare a work standard and continue to improve processes by correcting the differences between the standard and actual results. Our core asset kaizen method provides a standard that includes core asset types based on simple metrics, kaizen patterns representing expertise, and kaizen processes for continuous improvement. Categories and Subject Descriptors K.6.3 [Management of Computing and Information Systems]: Software Management (D.2.9) – Software development, Software maintenance, Software process. General Terms Management, Measurement, Economics. Keywords Software product line, Evolution, Core asset, Kaizen, Pattern. 1. INTRODUCTION 1.1 Product Line Engineering A software development company makes an effort to continuously develop software at lower cost, with higher quality and in a shorter time to meet customers’ requirements or strengthen its competitive position in a market. Software product line engineering is an emerging paradigm that helps the company reach its goal; considerable research efforts have been presented [9] [10]. Clements and Northrop define a product line as a set of software-intensive systems sharing a common, managed set of features that satisfy specific needs of a particular market or mission, and that are developed from a common set of core assets in a prescribed way [3]. In a software product line engineering paradigm, an organization draws a product roadmap, prepares software assets which are called core assets, and then develops software products by reusing core assets. The core assets are reusable software-related assets which are used in the production of more than one product in a software product line. A core asset may be an architecture, a software component, a process model, a plan, a document, or any other useful result of building a system [3]. 1.2 Core Asset Evolution and Kaizen The market, technology, and organization related to a product line change with time. The requirements for an existing product line, for example, removing defects or extending core assets, accumulate. A product line development organization should maintain and optimize a product line by evolving core assets. Evolution is any change in the quality, functionality, or implementation of the services offered by a system [2]. Change is not carried out in an instant; it is continuous. It is necessary to evolve core assets continuously. In addition, evolution should make things better rather than worse regardless of its goal. Therefore, evolution should improve things continuously. An important contribution to continuous process improvement is the kaizen. Kaizen is a movement that leads to continual, incremental improvement [7]. Kaizen is used in the Japanese manufacturing industry and is also an important factor in Japanese software processes [4]. Kaizen means continuous improvement involving everyone: executives, managers and workers. The multiplicative effect of the continuous improvement of every level of an organizational hierarchy drives the organization to a good direction. Top executives establish a kaizen-based policy. Managers establish work standards on the basis of the policy, and maintain and improve them. Workers engage in continuous self-development to become better problem solvers and enhance skills and job performance on the basis of the work standard [7]. 1.3 Lack of Detailed Evolution Knowledge A work standard plays an important role in successful kaizen activity. Kaizen begins with finding a problem or an unusual situation; the work standard helps an organization find a problem or an unusual situation by comparing the current situation with the standard. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SAC’07, March 11-15, 2007, Seoul, Korea. Copyright 2007 ACM 1-59593-480-4/07/0003…$5.00. 1207Kaizen activities include the following: - To operate in accordance with a work standard. - To evaluate the operation on the basis of the work standard. - To correct and improve the operation if deviation from the standard is recognized. - To feed back best practices to the standard. The above activities are continued to improve the operation and the standard. The software product line development paradigm is not sufficiently mature to provide a method of preparing such a standard. Product line research efforts provide suggestions for the preparation of the standard. Clements and Northrop define a set of 29 software product line practice areas and software product line practice patterns that give common product line problem/solution pairs based on the practice areas [3]．The practice areas are used to define the capability of an organization necessary for mastering a software product line approach. The practice patterns are used to give common product line problem/solution pairs, which help an organization choose appropriate practice areas. The practice areas and patterns are defined in a generic way; accordingly, various types of organizations can use them. Considering core asset evolution, an organization not only adds to