Change in perception of US security commitment

Data

News stories retrieved by keywords for dicplomary and military without specifing county names.

print(ndoc(toks)) # Number of news articles
## [1] 122814
toks_jp <- tokens_select(toks, c('日本*', '東京'), window = 100)

Commitment keywords

The Japanese keywords for security commitment are

print(dict[['ja']]['foreign policy']) # Japanese words for commitment
## Dictionary object with 1 primary key entry and 2 nested levels.
## - [foreign policy]:
##   - [commitment]:
##     - 関与, コミットメント, 参画, 参与, 参加
##   - [trust]:
##     - 信頼*, 信憑*, 信用*
##   - [concern]:
##     - 懸念, 危惧, 疑惧, 憂虞, 不安, 心配
##   - [isolationism]:
##     - 孤立*, 一国*, 単独*

These are translations of those English words

print(dict[['en']]['foreign policy']) # Japanese words for commitment
## Dictionary object with 1 primary key entry and 2 nested levels.
## - [foreign policy]:
##   - [commitment]:
##     - commit*
##   - [credibility]:
##     - trust*, reliabl*
##   - [concern]:
##     - concern*
##   - [isolationism]:
##     - isolation*, nation*, unilater*

Frequency of commitment keywords

This plot shows the the total number of times the keywords appeared in the newspaper.

mt <- dfm(toks, groups = 'year')
mt_commit <- dfm(tokens_lookup(toks, dict[['ja']]['foreign policy']), groups = 'year', tolower = FALSE)
plot_keywords(t(mt_commit))

Frequency of the US near commitment keywords

This chart shows the frequency of the US within 10 words from keywords (sub-categories are collapsed). Mentions of the US has gone up sharply after 2012. Solid line is the frequency in the contexts of the US-Japan relation, while dotted line is the frequency in any context.


dict_geo_sub <- dict_geo[['AMERICA']][['NORTH']]['US']
mt_jp <- count_keywords(toks_jp, dict_geo_sub, dict[['ja']]['foreign policy'])
plot_keywords(mt_jp)
mt_gl <- count_keywords(toks, dict_geo_sub, dict[['ja']]['foreign policy'])
plot_keywords(mt_gl, TRUE)