2.2 Seeking Specific Keywords and Co-word Mapping
Comparison Between National and Local Newspapers
Since March 11, there has been a large amount of information while discourse
related to 3.11 has been rampant. Thus, we conducted quantitative analysis of
discourses regarding 3.11 in legacy and social media. We conducted frequency
analysis, analysis of specific keywords of each week, and network analysis focusing
on the co-occurrence of keywords (co-word).
For analysis of frequency and specific keywords ranking
6 of each week, we used
KH coder (http://khc.sourceforge.net/) developed by Koichi Higuchi [12, 13].
We then searched for the target keywords in each text. We employed co-word
analysis to describe Japanese media trends on the 3.11. The analysis employed in
the present study relied on previous research by Leydesdorff and Hellsten [14, 15].
They expressed co-words such as “the carriers of meaning across different
domains” ([15]: 232). The method of analysis here basically depended on previous
studies by Leydesdorff and Hellsten [14, 15]. Salton’s cosine was calculated as the
similarity index [16–18]. In all analysis of this chapter, the cosine threshold was
settled at 0.375. Networks have been described by Pajek [19]. For the configuration
algorithm for nodes, the Kamada and Kawai algorithm was used [20]. As the index
of centrality, “Betweenness centrality” was used [21].
3 Results
We would like to discuss another gap: “gap of information, which is focused and
taken up by and in media”. Figure 2 shows the time-lined change of article number
and appearance ratio of keywords of Asahi-shimbun and Kahoku-Shinpo. Asahishimbun is one of the most prestigious newspapers in Japan. Kahoku-Shinpo is the
most famous and important block newspaper in the Miyagi Prefecture. Looking at
this line-chart of Asahi-shimbun, we analyzed the oscillation cycle of article
numbers and the change of trend in keyword appearance. The appearance ratio of
“Earthquake” gradually decreased, but on the other hand, the ratio of “NPP”
increased. At the same time, “tsunami” marked a lower score than “NPP.”
Meanwhile, it is clear that Kahoku-Shinpo has different trends from Asahi-shimbun.
In Kahoku-Shinpo, the appearance ratio of “tsunami” continued to remain equal to
“NPP.” The oscillation cycle of article number in Asahi-shimbun had the tendency
to decrease, whereas, there are no such trends of decrease in article numbers in
Kahoku-Shinpo.
6
For making ranking of specific keywords of each time-tag, KH coder calculated Jaccard index
between time-tag and keywords.
Deprivation of Media Attention by Fukushima Daiichi …
117
Comparison Between National and Local Newspapers
Since March 11, there has been a large amount of information while discourse
related to 3.11 has been rampant. Thus, we conducted quantitative analysis of
discourses regarding 3.11 in legacy and social media. We conducted frequency
analysis, analysis of specific keywords of each week, and network analysis focusing
on the co-occurrence of keywords (co-word).
For analysis of frequency and specific keywords ranking
6 of each week, we used
KH coder (http://khc.sourceforge.net/) developed by Koichi Higuchi [12, 13].
We then searched for the target keywords in each text. We employed co-word
analysis to describe Japanese media trends on the 3.11. The analysis employed in
the present study relied on previous research by Leydesdorff and Hellsten [14, 15].
They expressed co-words such as “the carriers of meaning across different
domains” ([15]: 232). The method of analysis here basically depended on previous
studies by Leydesdorff and Hellsten [14, 15]. Salton’s cosine was calculated as the
similarity index [16–18]. In all analysis of this chapter, the cosine threshold was
settled at 0.375. Networks have been described by Pajek [19]. For the configuration
algorithm for nodes, the Kamada and Kawai algorithm was used [20]. As the index
of centrality, “Betweenness centrality” was used [21].
3 Results
We would like to discuss another gap: “gap of information, which is focused and
taken up by and in media”. Figure 2 shows the time-lined change of article number
and appearance ratio of keywords of Asahi-shimbun and Kahoku-Shinpo. Asahishimbun is one of the most prestigious newspapers in Japan. Kahoku-Shinpo is the
most famous and important block newspaper in the Miyagi Prefecture. Looking at
this line-chart of Asahi-shimbun, we analyzed the oscillation cycle of article
numbers and the change of trend in keyword appearance. The appearance ratio of
“Earthquake” gradually decreased, but on the other hand, the ratio of “NPP”
increased. At the same time, “tsunami” marked a lower score than “NPP.”
Meanwhile, it is clear that Kahoku-Shinpo has different trends from Asahi-shimbun.
In Kahoku-Shinpo, the appearance ratio of “tsunami” continued to remain equal to
“NPP.” The oscillation cycle of article number in Asahi-shimbun had the tendency
to decrease, whereas, there are no such trends of decrease in article numbers in
Kahoku-Shinpo.
6
For making ranking of specific keywords of each time-tag, KH coder calculated Jaccard index
between time-tag and keywords.
Deprivation of Media Attention by Fukushima Daiichi …
117