Faculty Profiles - OHIRA Masao

Published Papers - OHIRA Masao

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Clustering OSS License Statements Toward Automatic Generation of License Rules

Yunosuke Higashi, Yuki Manabe, Masao Ohira

PROCEEDINGS 7TH INTERNATIONAL WORKSHOP ON EMPIRICAL SOFTWARE ENGINEERING IN PRACTICE (IWESEP 2016) ( IEEE ) 30 - 35 2016 [Refereed]

Reusing open source software (OSS) components for own software products has become common in the modern software development. Automated license identification tools has been proposed to help developers identify OSS licenses, since a large number of licenses sometimes must be checked to be reused. Of the existing tools, Ninka [1] can most correctly identify licenses of each source file by using regular expressions. In case Ninka does not have license identification rules for unknown licenses, Ninka reports they are "unknown licenses" which must be checked by developers manually. Since completely new or derived OSS licenses appear nearly every year, a license identification tool should be appropriately maintained by adding regular expressions corresponding to the new licenses. The final goal of our study is to construct a method to automatically create candidates of license rules to be added to a license identification tool such as Ninka. Toward achieving the goal, files identified as unknown licenses must be classified by license firstly. In this paper, we propose a hierarchical clustering which divides unknown licenses into clusters of files with a single license. We conduct a case study to confirm the usefulness of our clustering method when it is applied for classifying 2,838 unknown license files of Debian v7.8.0. As a result, it is confirmed that our method can create clusters which are suitable as candidates for generating license rules automatically.

DOI

A Case Study on the Misclassification of Software Performance Issues in an Issue Tracking System

Masao Ohira, Hayato Yoshiyuki, Yosuke Yamatani

2016 IEEE/ACIS 15TH INTERNATIONAL CONFERENCE ON COMPUTER AND INFORMATION SCIENCE (ICIS) ( IEEE COMPUTER SOC ) 855 - 860 2016 [Refereed]

In this study we focus on the misclassification of issue reports regarding software performance in OSS development. IEEE Std 610 [1] defines performance as "The degree to which a system or component accomplishes its designated functions within given constraints, such as speed, accuracy, or memory usage." The definition implies that there is no rigorous criteria nor quantitative measure to detect a software performance problem, but rather it relies on a subjective judgement. OSS users sometimes mistakenly report a performance bug as a request for improving software performance and sometimes mistakenly report an improvement request for fixing a performance bug. The misclassification of report types can impedes the efficient bug-fix process in OSS development, since OSS developers preferentially spend time fixing bugs which might be improvement requests (i.e., not bugs) in reality. In this paper we strengthen our previous study for the Apache Wicket project by manually inspecting 1,000 bugs and 1,000 improvement requests respectively to more precisely understand the impacts of the misclassification on the bug-fix process in OSS development.

DOI

機械学習を用いたテキスト分類によるライセンス特定のためのルール作成プロセス支援

東裕之輔, 眞鍋雄貴, 大平雅雄

ソフトウェア・シンポジウム 2015 in 和歌山 70 - 79 2015.06 [Refereed]

A Dataset of High Impact Bugs: Manually-Classified Issue Reports

Masao Ohira, Yutaro Kashiwa, Yosuke Yamatani, Hayato Yoshiyuki, Yoshiya Maeda, Nachai Limsettho, Keisuke Fujino, Hideaki Hata, Akinori Ihara, Kenichi Matsumoto

12TH WORKING CONFERENCE ON MINING SOFTWARE REPOSITORIES (MSR 2015) ( IEEE ) 518 - 521 2015 [Refereed]

The importance of supporting test and maintenance activities in software development has been increasing, since recent software systems have become large and complex. Although in the field of Mining Software Repositories (MSR) there are many promising approaches to predicting, localizing, and triaging bugs, most of them do not consider impacts of each bug on users and developers but rather treat all bugs with equal weighting, excepting a few studies on high impact bugs including security, performance, blocking, and so forth. To make MSR techniques more actionable and effective in practice, we need deeper understandings of high impact bugs. In this paper we introduced our dataset of high impact bugs which was created by manually reviewing four thousand issue reports in four open source projects (Ambari, Camel, Derby and Wicket).

DOI

Predicting Bug-Fix Time Using Social Relationships between Assignors and Assignees in OSS Development

吉行勇人, 大平雅雄, 戸田航史

コンピュータソフトウェア ( Japan Society for Software Science and Technology ) 32 ( 2 ) 2.128-2.134 (J-STAGE) - 2_134 2015 [Refereed]

A large number of bugs are reported to a large-scale open source software (OSS) project. Since it is very difficult to fix all the bugs, a manager in the project needs to know time to fix bugs to decide which bugs should be fixed before the next release. In this paper we focus on social relationships between assignors and assignees and construct prediction models based on a random forest method and logistic regression, in order to predict the time to fix bugs. As a result of our experiment, we show that our model predicts more accurately whether a bug is fixed within a day or not, compared with the existing prediction model.

DOI

ソフトウェア品質の第三者評価における探索的データ解析ツールの利用とその効果:OSSデータを対象とした検証実験

大平雅雄, 伊原彰紀, 中野大輔, 松本健一（Part： Lead author )

SEC Journal ( 情報処理推進機構技術本部ソフトウェア・エンジニアリング・センター ) 10 ( 1 ) 24 - 31 2014.03 [Refereed]

Adaptive Search Framework: Better Search Result for Community

Papon Yongpisanpop, Masao Ohira, Akinori Ihara, Kenichi Matsumoto

情報社会学会誌 8 ( 2 ) 29 - 43 2014.03 [Refereed]

An Exploratory Analysis for Studying Software Evolution: Time-Delayed Correlation Analysis

Yosuke Yamatani, Masao Ohira

2014 6TH INTERNATIONAL WORKSHOP ON EMPIRICAL SOFTWARE ENGINEERING IN PRACTICE (IWESEP 2014) ( IEEE ) 13 - 18 2014 [Refereed]

We propose an exploratory analysis method for software repositories so that you can study software evolution without an explicit goal. The method extends the traditional correlation analysis to consider a time lag between any pair of metrics. Using data collected from three kinds of repositories, the method automatically calculates optimal parameters to deal with a time lag between metrics and returns the highest correlation coeffcient for each pair of metrics. Our case study using one hundred metrics data from three OSS projects shows that the method allows us to find unexpected relationships in some pairs of metrics if we only use the traditional correlation analysis and that using such relationships can be used to build an analysis goal to understand software evolution.

DOI

Early Identification of Future Committers in Open Source Software Projects

Akinori Ihara, Yasutaka Kamei, Masao Ohira, Ahmed E. Hassan, Naoyasu Ubayashi, Ken-ichi Matsumoto

2014 14TH INTERNATIONAL CONFERENCE ON QUALITY SOFTWARE (QSIC 2014) ( IEEE COMPUTER SOC ) 47 - 56 2014 [Refereed]

There exists two types of developers in Open Source Software (OSS) projects: 1) Committers who have permission to commit edited source code to the Version Control System (VCS), 2) Developers who contribute source code but cannot commit to the VCS directly. In order to develop and evolve high quality OSS, projects are always in search of new committers. OSS projects often promote strong developers to become committers. When existing committers find strong developers, they propose their promotion to a committer role. Delaying the committer-promotion might lead to strong developers departing from an OSS project and the project losing them. However early committer-promotion comes with its own slew of risks as well (e.g., the promotion of inexperienced developers). Hence, committer-promotion decisions are critical for the quality and successful evolution of OSS projects. In this paper, we examine the committer-promotion phenomena for two OSS projects (Eclipse and Firefox). We find that the amount of activities by future committers was higher than the amount of activities by developers who did not become committers). We also find that some developers are promoted to a committer role very rapidly (within a few month) while some of developers take over one year to become a committer. Finally, we develop a committer-identification model to assist OSS projects identifying future committers.

DOI

A Pilot Study of Diversity in High Impact Bugs

Yutaro Kashiwa, Hayato Yoshiyuki, Yusuke Kukita, Masao Ohira

2014 IEEE INTERNATIONAL CONFERENCE ON SOFTWARE MAINTENANCE AND EVOLUTION (ICSME) ( IEEE COMPUTER SOC ) 536 - 540 2014 [Refereed]

Since increasing complexity and scale of modern software products imposes tight scheduling and resource allocations on software development projects, a project manager must carefully triage bugs to determine which bug should be necessarily fixed before shipping. Although in the field of Mining Software Repositories (MSR) there are many promising approaches to predicting, localizing, and triaging bugs, most of them do not consider impacts of each bug on users and developers but rather treat all bugs with equal weighting, excepting a few studies on high impact bugs including security, performance, blocking, and so forth. To make MSR techniques more actionable and effective in practice, we need deeper understandings of high impact bugs. In this paper we report our pilot study on high impact bugs, which classifies bugs reported to four open source projects into six types of high impact bugs.

DOI

Predicting the Bug Fixing Time Based on the Bug Assignment Patterns in OSS Development

正木仁, 大平雅雄, 伊原彰紀, 松本健一

情報処理学会論文誌ジャーナル(CD-ROM) 54 ( 2 ) 933 - 944 2013.02 [Refereed]

Predicting the Bug Fixing Time Based on the Bug Assignment Patterns in OSS Development

正木仁, 大平雅雄, 伊原彰紀, 松本健一

情報処理学会論文誌 ( 情報処理学会 ) 54 ( 2 ) 933 - 944 2013.02 [Refereed]

大規模OSSプロジェクトには日々大量の不具合が報告されており，不具合修正時間（OSSプロジェクトに報告された不具合が解決するまでに要する時間）をより正確に見積もることが重要になってきている．OSSプロジェクト管理者は，次期バージョンのリリースまでにどの不具合を修正すべきかを判断しなければならないためである．しかしながら，不具合の修正範囲の大きさや問題の複雑さの違い，ボランティアを主体とする開発者のスキルセットの違いなどの要因によって，個々の不具合の修正時間を見積もることは容易ではない．そのため近年，OSS開発における不具合修正時間の予測に関する研究がさかんに行われている．本論文では，不具合割当てパターンを用いて不具合修正時間の予測モデルを構築する．不具合割当てパターンとは，不具合修正タスク割当て時の不具合報告者・管理者・修正担当者の3者の社会的関係を分類したものである．不具合割当てパターンの違いにより，修正作業にとりかかるまでの時間および修正作業自体に要する時間はそれぞれ大きく異なることが知られている．従来研究の多くは不具合情報（重要度や優先度など）に基づいて予測モデルを構築しているが，不具合管理パターンを考慮することでさらなる予測精度の向上を期待できる．本論文では，Eclipse PlatformおよびJDTを対象として構築した予測モデルの評価を行った．実験の結果，不具合割当てパターンが不具合修正時間の予測精度向上に寄与するとともに，指定期間内（1週間以内など）に不具合修正が完了するか否かの判断を支援できることが分かった．さらに，本予測モデルを利用することで，Platformで約16%，JDTで約10%多くの不具合を修正可能と判断できることが分かった．The number of reported bugs has been increasing especially in large-scale open source software (OSS) projects. Project managers in the projects have to decide which bugs should be resolved until they release the next version of their products. However it is not easy to estimate the time to resolve each bug due to the differences of the size of required modifications, the difficulty of each modification, skill set of each developer, and so forth. To address this issue, many studies have tried to predict the bug fixing time in OSS development. In this paper we constructs a prediction model for the bug fixing time, using the bug assignment patterns which have an impact on developer's performance of fixing bugs. The bug assignment patterns categorize the social relationships among bug reporters, managers, and developers in assigning bug fixing tasks. While most studies in the past only used the information extracted from bug reports itself, taking the bug assignment patterns into account would lead to prediction results with higher accuracy. Using data from the Eclipse Platform and JDT projects, we evaluates the prediction model. As a result, we found that the bug assignment patterns improved the prediction accuracy and help OSS managers make sure if a target bug will be resolved in a specified period (e.g., one week). We also found that our prediction model can contribute to resolve more bugs until the specified release (about 16% in Platform and about 10% in JDT).

A new perspective on the socialness in bug triaging: A case study of the eclipse platform project

Masao Ohira, Hayato Yoshiyuki

2013 5th International Workshop on Social Software Engineering, SSE 2013 - Proceedings 29 - 32 2013 [Refereed]

This paper explores how social relationships among developers impact on the efficiency of bug fixes. From the case study of the Eclipse Platform project, we found that (1) past achievements of bug triaging by particular pairs of assignors and fixers do not necessarily impact on the time to fix bugs, (2) rather, the time required to fix a bug can depend on who assigns the bug fixing task to a fixer. These findings would imply that we need to not only consider who should fix this bug? but also take into account a fixer's perspective who should assign this bug? or who should ask to whom?, in order to better support the bug triaging process. Copyright 2013 ACM.

DOI

An Algorithm for Gradual Patch Acceptance Detection in Open Source Software Repository Mining

Passakorn Phannachitta, Akinori Ihara, Pijak Jirapiwong, Masao Ohira, Ken-ichi Matsumoto

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES ( IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG ) E95A ( 9 ) 1478 - 1489 2012.09 [Refereed]

Nowadays, software development societies have given more precedence to Open Source Software (OSS). There is much research aimed at understanding the OSS society to sustain the OSS product. To lead an OSS project to a successful conclusion, researchers study how developers change source codes called patches in project repositories. In existing studies, we found an argument in the conventional patch acceptance detection procedure. It was so simplified that it omitted important cases from the analysis, and would lead researchers to wrong conclusions. In this research, we propose an algorithm to overcome the problem. To prove out our algorithm, we constructed a framework and conducted two case studies. As a result, we came to a new and interesting understanding of patch activities.

DOI

Good or Bad Committers? - A Case Study of Committer's Activities on the Eclipse's Bug Fixing Process

Anakorn Jongyindee, Masao Ohira, Akinori Ihara, Ken-ichi Matsumoto

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS ( IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG ) E95D ( 9 ) 2202 - 2210 2012.09 [Refereed]

There are many roles to play in the bug fixing process in open source software development. A developer called "Committer", who has a permission to submit a patch into a software repository, plays a major role in this process and holds a key to the successfulness of the project. Despite the importance of committer's activities, we suspect that sometimes committers can make mistakes which have some consequences to the bug fixing process (e.g., reopened bugs after bug fixing). Our research focuses on studying the consequences of each committer's activities to this process. We collected each committer's historical data from the Eclipse-Platform's bug tracking system and version control system and evaluated their activities using bug status in the bug tracking system and commit log in the version control system. Then we looked deeper into each committer's characteristics to see the reasons why some committers tend to make mistakes more than the others.

DOI

OSS開発における不具合修正プロセスの現状と課題:不具合修正時間の短縮化へ向けた分析

伊原彰紀, 大平雅雄, 松本健一

情報社会学会誌 6 ( 2 ) 5 - 16 2012.03 [Refereed]

A Candidate Committer Prediction Based on Developer Activities in Open Source Software Projects

伊原彰紀, 亀井靖高, 大平雅雄, 松本健一, 鵜林尚靖

( 電子情報通信学会 ) 2012.02

本論文では，オープンソースソフトウェア（OSS）プロジェクトに参加する一般開発者の中からコミッターに推薦されるべき有能な開発者（コミッター候補者）を見つけ出すことを目的とする．近年，数百件もの不具合がプロジェクトに日々，報告されている現状から，コミッターへの過度な負担が原因となり不具合修正の長期化を招いている．コミッターの負担を軽減させるためにコミッターを増員するという手段があるが，プロジェクトに参加する一般開発者の中からコミッター候補者を見つけることは容易ではない．本論文では，コミッター候補者を見つけ出すために既存コミッターの過去の活動とその活動量を分析し，コミッター予測モデルを構築した．モデル構築には，コミッター候補者と一般開発者の活動（パッチの投稿，パッチの検証，開発に伴う議論）履歴とプロジェクトでの活動期間を用いた．分析の結果，継続的にパッチの投稿，パッチの検証を行う開発者がコミッターに昇格していることが分かった．また，構築したコミッター予測モデルは，ランダムに予測する場合に比べて予測精度が5～7倍高いことが分かった．

A Candidate Committer Prediction Based on Developer Activities in Open Source Software Projects

IHARA Akinori, KAMEI Yasutaka, OHIRA Masao, MATSUMOTO Ken-ichi, UBAYASHI Naoyasu

The IEICE transactions on information and systems (Japanese edetion) ( The Institute of Electronics, Information and Communication Engineers ) 95 ( 2 ) 237 - 249 2012.02

本論文では,オープンソースソフトウェア(OSS)プロジェクトに参加する一般開発者の中からコミッターに推薦されるべき有能な開発者(コミッター候補者)を見つけ出すことを目的とする.近年,数百件もの不具合がプロジェクトに日々,報告されている現状から,コミッターへの過度な負担が原因となり不具合修正の長期化を招いている.コミッターの負担を軽減させるためにコミッターを増員するという手段があるが,プロジェクトに参加する一般開発者の中からコミッター候補者を見つけることは容易ではない.本論文では,コミッター候補者を見つけ出すために既存コミッターの過去の活動とその活動量を分析し,コミッター予測モデルを構築した.モデル構築には,コミッター候補者と一般開発者の活動(パッチの投稿,パッチの検証,開発に伴う議論)履歴とプロジェクトでの活動期間を用いた.分析の結果,継続的にパッチの投稿,パッチの検証を行う開発者がコミッターに昇格していることが分かった.また,構築したコミッター予測モデルは,ランダムに予測する場合に比べて予測精度が5〜7倍高いことが分かった.

Lessons Learned from Collaborative Research in Software Engineering: A Student's Perspective.

Anakorn Jongyindee, Pattara Leelaprute, Masao Ohira, Ken-ichi Matsumoto

13th ACIS International Conference on Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing, SNPD 2012, Kyoto, Japan, August 8-10, 2012 ( IEEE Computer Society ) 494 - 497 2012 [Refereed]

DOI

The Impact of Bug Management Patterns on Bug Fixing: A Case Study of Eclipse Projects

Masao Ohira, Ahmed E. Hassan, Naoya Osawa, Ken-ichi Matsumoto

2012 28TH IEEE INTERNATIONAL CONFERENCE ON SOFTWARE MAINTENANCE (ICSM) ( IEEE ) 264 - 273 2012 [Refereed]

An efficient bug management process is critical for the success of software projects. Prior work has focused on improving this process, for example, by automating bug triaging, detecting duplicate bugs, and understanding the rationale for re-opening bugs. This paper continues this line of work by exploring the people who are involved in the bug management process. In particular we develop four patterns that distill the different relations between the people involved in the process: the reporter, triager, and fixer of a bug. Through a case study on the Eclipse Platform and JDT projects, we demonstrate that these patterns have an impact on the efficiency of the bug management process. For example, we find that using our patterns project personnel can improve their efficiency through better communication about bugs before assigning them.

DOI

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Published Papers - OHIRA Masao