著者
Naoki Kobayakawa Mitsuyoshi Imamura Kei Nakagawa Kenichi Yoshida
出版者
Information Processing Society of Japan
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.28, pp.650-657, 2020 (Released:2020-09-15)
参考文献数
28

Open source software (OSS) has become indispensable to our society. The success of OSS depends on the participation of a large number of developers or maintainers (contributors). Shedding light on the mechanisms of their participation has been an important academic and practical matter. One aspect to decide participation is the future prospects of a project. However, the causal mechanism behind participation has yet to be studied exhaustively and remains unclear. In this study, we used cryptocurrency projects, many of them were developed on GitHub, to better understand this mechanism. Both GitHub and cryptocurrencies are highly transparent, i.e., information is fully disclosed; we can analyze relevant information on a project, such as the contributors' activities, financial information, and development status. We adopted market capitalization as the substitution index of future prospects and the number of contributors and analyzed the relationship using time series analysis techniques, such as the Granger causality test and regression. We found that the number of contributors increases two months after market capitalization increases. This quantifies the impact of the future prospects of the project, i.e., of the market capitalization of a cryptocurrency, on the participation of contributors.
著者
Kenichi Yoshida
雑誌
情報処理学会論文誌 (ISSN:18827764)
巻号頁・発行日
vol.60, no.9, 2019-09-15

\n------------------------------This is a preprint of an article intended for publication Journal ofInformation Processing(JIP). This preprint should not be cited. Thisarticle should be cited as: Journal of Information Processing Vol.27(2019) (online)DOI http://dx.doi.org/10.2197/ipsjjip.27.613------------------------------
著者
Kenichi Yoshida Akito Sakurai
出版者
一般社団法人 人工知能学会
雑誌
人工知能学会論文誌 (ISSN:13460714)
巻号頁・発行日
vol.30, no.5, pp.683-692, 2015-09-01 (Released:2015-09-15)
参考文献数
24
被引用文献数
1

Efficient market hypothesis is widely accepted in financial market studies and entails the unpredictability of future stock prices. In this study, we show that a simple analysis can classify short-term stock price changes with an 82.9% accuracy. Our analysis uses the order book information of high-frequency trading. The volume of high-frequency trading, which is responsible for short-term stock price changes, is increasing dramatically; therefore, our study suggests the importance of analyzing short-term market fluctuations, an aspect that is not well studied in conventional market theories. The experimental results also suggest the importance of the new data representation and analysis methods we propose, neither of which have been thoroughly investigated in conventional financial studies.
著者
Hiroki Usuku Eiichiro Yamamoto Fumi Oike Tatsuya Yoshinouchi Kanako Imamura Kenichi Yoshida Daisuke Kanesaki Yasuhiro Toma Ayako Tomita Yuji Ogata Seiki Matsumoto Yoshio Iwayama Tomoko Sassa Shinji Tanaka Yoko Fukuyoshi Tamami Matsumoto Eiichiro Tanaka Hiroyuki Shono Kazuhiro Nishigami Kenichi Tsujita Hirotaka Matsui
出版者
The Japanese Circulation Society
雑誌
Circulation Reports (ISSN:24340790)
巻号頁・発行日
vol.2, no.6, pp.297-305, 2020-06-10 (Released:2020-06-10)
参考文献数
17

Background:There are few reports on current awareness and status of transthoracic echocardiography (TTE), including the actual performance rate according to echocardiographic guidelines, in a specific area or region.Methods and Results:This cross-sectional survey study was conducted in Kumamoto Prefecture from October 2018 to March 2019. There are 366 medical institutions advocating cardiology in Kumamoto Prefecture. Of these, 259 (101 hospitals and 158 clinics) returned questionnaires regarding TTE. In all, 150,570 TTEs were performed in 2017. Of these, 132,771 (88%) were performed in hospitals and 17,799 (12%) were performed in clinics. Physicians performed only 5% of TTEs, whereas sonographers performed 86%. Although the modified Simpson method was performed in 90% of hospitals, 3-dimensional echocardiography was performed in only 2% of hospitals. In addition, the left atrial volume index was not examined in approximately 60% of hospitals, and the mean E/E′ ratio was not examined in 80% of hospitals. Multivariable logistic regression analysis revealed that having a Fellow of the Japan Society of Ultrasonic in Medicine was significantly and independently associated with guideline-oriented TTE (odds ratio 9.43; 95% confidence interval 1.22–72.71, P<0.05).Conclusions:The rate of echocardiographic measurements performed according to echocardiographic guidelines is exceptionally low in Kumamoto Prefecture. Sufficient dissemination of echocardiographic guidelines may be important in improving this rate.
著者
Kazunori Fujiwara Akira Sato Kenichi Yoshida
出版者
一般社団法人 情報処理学会
雑誌
Journal of Information Processing (ISSN:18826652)
巻号頁・発行日
vol.21, no.3, pp.517-526, 2013 (Released:2013-07-15)
参考文献数
11
被引用文献数
1

The Domain Name System (DNS) is a key naming system used in the Internet. Recently, the deployment of IPv6 (especially after the World IPv6 Launch) and DNS prefetching in web browsers has significantly changed DNS usage. Furthermore, content delivery networks (CDNs) use complicated DNS configurations together with small TTL values to control their traffic. These three factors significantly increase DNS traffic. Thus, the importance of DNS traffic analysis has been increasing to properly maintain DNS operations. This paper presents an analysis of DNS full resolver traffic at the University of Tsukuba in Japan. What we found are 1) The deployment of IPv6 has increased queries from clients as much as 41%, 2) The deployment of CDNs increases the use of small TTL values, the use of CNAME resource records and the use of out-of-bailiwick DNS server names. Since these increases are making the DNS cache hit rate low and the DNS response slow without recognition by Internet users, this paper seeks to warn application designers of potential system design risks in current Internet applications.
著者
Hiroshi Uehara Kenichi Yoshida
出版者
Information Processing Society of Japan
雑誌
IPSJ Digital Courier (ISSN:13497456)
巻号頁・発行日
vol.2, pp.145-154, 2006 (Released:2006-03-08)
参考文献数
15

This paper proposes a method for creating the viewers' side annotations that reflect viewers' attentions on TV dramas. Internet bulletin boards are filled with large amount of viewers' dialogues concerning TV programs. Our approach is to extract the viewers' attention embedded in these dialogues and express them in the form of the graphical structures called attention graphs. The attention graphs act as viewers' side annotations. Viewers' side annotations assist in providing viewers with hints to locate their favorite scenes in full-length TV programs. In general, Internet bulletin boards are described without any particular order and are expressed in a poor grammatical manner. Our approach is to statistically recognize the notable frequencies of the words which represent viewers' attentions out from such unstructured documents. Attention graphs are the outcome of this approach. Attention graphs are evaluated by three types of tests. The test results demonstrate that attention graphs sufficiently act as viewers' side annotations, in terms of pointing out which scene the viewers pay attention to and clarifying how deeply viewers are impressed by the scenes.