wordmap is a semi-supervised algorithm for multinomial document classification originally created for newsmap. wordmap is separated from newsmap to expand the score of its application beyond geographical classification of news.
The algorithm is also useful in extracting features associated with document meta-data (industry group, patent class etc.) from vary larger corpora. The list of features could be used to create a lexicon to perform dictionary analysis.
wordmap is available on CRAN since the v0.8.0 You can install the package using the R command.
install.packages("wordmap")If you want to the latest version, please install by running this command in R. You need to have devtools installed beforehand.
install.packages("devtools")
devtools::install_github("koheiw/wordmap")In this example, we identify topics of sentences from using a seed topic
dictionary adopted from Watanabe & Zhou
(2020).
data_corpus_ungd2017 contains transcripts of speeches delivered at the
United Nations General Assembly in 2017.
require(quanteda)
## Loading required package: quanteda
## Package version: 4.1.0
## Unicode version: 15.1
## ICU version: 74.1
## Parallel computing: 16 of 16 threads used.
## See https://quanteda.io for tutorials and examples.
require(wordmap)
## Loading required package: wordmap
dict <- data_dictionary_topic
print(dict)
## Dictionary object with 6 key entries.
## - [greeting]:
## - greet*, thank*, congratulat*, sir, express*
## - [un]:
## - united nations, international court*, security council, general assembly, organization*, reform*, secretary-general, resolution*, permanent member*, charter*, session*, conference*
## - [security]:
## - secur*, kill*, attack*, dispute*, victim*, peac*, terror*, weapon*, nuclear*, conflict*, war*, disarmament*, threat*, cris*, solution*, settlement*, force*, destruction*, militar*, violence* [ ... and 2 more ]
## - [human]:
## - human rights, violat*, race*, dignit*, protect*, citizen*, educat*
## - [democracy]:
## - democra*, autocra*, dictator*, vote*, represent*, elect*, leader*, president*, government*, leadership*
## - [development]:
## - develop*, market*, investment*, econom*, climate change, assistance*, sustain*, povert*, trade*, grow*, social*, environment*, prosperit*, progress*, financ*, cooperation*
corp <- data_corpus_ungd2017 %>%
corpus_reshape()
toks <- tokens(corp, remove_url = TRUE, remove_numbers = TRUE) %>%
tokens_remove(stopwords("en"), min_nchar = 2, padding = TRUE) #%>%
#tokens_remove("^[A-Z]", valuetype = "regex", case_insensitive = FALSE, padding = TRUE)
dfmt_feat <- dfm(toks, remove_padding = TRUE) %>%
dfm_trim(min_termfreq = 5)
dfmt_label <- tokens_lookup(toks, dict) %>%
dfm()
map <- textmodel_wordmap(dfmt_feat, dfmt_label)
coef(map)
## $greeting
## express congratulate thank thanks congratulations
## 11.986522 11.814299 11.752273 10.894463 10.730899
## expressed greetings expression sir congratulating
## 10.450737 10.102669 10.060145 9.969254 9.758163
##
## $un
## session organization reform secretary-general
## 9.148177 9.137369 8.923089 8.846157
## resolution resolutions conference charter
## 8.433594 8.311070 8.298578 8.292274
## organizations reforms
## 8.157032 7.864775
##
## $security
## peace security nuclear terrorism weapons conflict war peaceful
## 9.487776 9.347336 8.335005 8.332907 8.083790 8.008265 7.854679 7.791758
## conflicts threat
## 7.747497 7.656765
##
## $human
## citizens education protect protection dignity violations protecting
## 10.615543 10.497122 10.342014 10.175012 10.070607 9.669904 9.422653
## violation protected race
## 9.141037 9.141037 8.747592
##
## $democracy
## government president democratic democracy leadership leaders
## 10.751528 10.326801 9.886474 9.471213 9.403103 9.251157
## election governments elections represent
## 9.220866 8.958655 8.543480 8.512740
##
## $development
## development sustainable economic cooperation social poverty
## 10.045804 9.524120 9.034501 8.712604 8.394841 8.260474
## progress developing environment assistance
## 8.227581 8.040148 7.911177 7.858847dat <- data.frame(text = corp, topic = predict(map))| text | topic | |
|---|---|---|
| Afghanistan.1 | As I stand here before the General Assembly today, I am reminded that the wise men and women of 1945 displayed a unique capacity to learn from and act on the lessons of history. | un |
| Afghanistan.2 | Shaped by the Great Depression and tempered by the carnage of the Second World War, they established global order through institutions that would provide security and stability for generations to come. | security |
| Afghanistan.3 | The United Nations, the International Monetary Fund, the World Bank and other organizations were founded to coordinate responses to international challenges and to make crimes against humanity a thing of the past. | un |
| Afghanistan.4 | There can be little doubt that today the scale, scope and speed of their imagination and efforts have not yet been matched. | security |
| Afghanistan.5 | But future historians will judge those institutions on how they respond to the challenges of today and the challenges we must confront in the future. | human |
| Afghanistan.6 | As global leaders, we seek certainty and familiarity in the rules of the game that dominated the twentieth century. | democracy |
| Afghanistan.7 | But in today’s ever-changing world, the dominant contextual characteristic defining our times is extreme uncertainty. | security |
| Afghanistan.8 | It is easy to illustrate this uncertainty by looking at threats we are facing - to our economies, our security and our values. | security |
| Afghanistan.9 | There is an emerging consensus that advanced economies have yet to arrive at proper growth models to overcome high unemployment, decreasing income and wealth inequality. | development |
| Afghanistan.10 | The threat of economic crisis, therefore, still hangs over us. | security |
Create a quanteda dictionary object from the extracted features. The dictionary could be use to perform analysis of other corpora.
as.dictionary(map, n = 100)
## Dictionary object with 6 key entries.
## - [greeting]:
## - express, congratulate, thank, thanks, congratulations, expressed, greetings, expression, sir, congratulating, expressing, expresses, congratulates, expressions, lajčák, miroslav, outset, warmly, warm, preside [ ... and 80 more ]
## - [un]:
## - session, organization, reform, secretary-general, resolution, resolutions, conference, charter, organizations, reforms, seventy-first, seventy, organization's, reforming, commissioner, seventy-second, reformed, repositioning, twenty-third, organizational [ ... and 80 more ]
## - [security]:
## - peace, security, nuclear, terrorism, weapons, conflict, war, peaceful, conflicts, threat, solution, crisis, violence, fight, threats, terrorist, force, military, crises, destruction [ ... and 80 more ]
## - [human]:
## - citizens, education, protect, protection, dignity, violations, protecting, violation, protected, race, violate, violated, citizenship, educational, citizen, violates, protectionism, educated, violating, protects [ ... and 80 more ]
## - [democracy]:
## - government, president, democratic, democracy, leadership, leaders, election, governments, elections, represent, representative, government's, represents, elected, represented, representation, representatives, leader, electoral, president's [ ... and 80 more ]
## - [development]:
## - development, sustainable, economic, cooperation, social, poverty, progress, developing, environment, assistance, prosperity, growth, economy, financial, trade, developed, financing, investment, environmental, growing [ ... and 80 more ]