The health and social welfare sector is changing from a provider-oriented to a consumer-oriented customized service system. It is important to use social big data to readily recognize these changes and to identify issues in the health and welfare sector. The use of social big data is on increasing demand as big data analytics has improved rapidly and an ever-growing amount of unstructured big data is available for collection and analysis. In this study, we examined health and welfare issues related to blockchain technology, which is widely regarded as an essential feature of the fourth industrial revolution era. The issue of blockchain first came to the fore of social attention in connection with crypto-currency. But the blockchain technology is evolving rapidly and its use is increasing across both the private and public sectors. Here, blockchain keywords and documents related to health and welfare keywords are collected together to see how blockchain technology is being used in health and social welfare. In order to investigate differences in priority issues in blockchain technology between Korea and other countries, we collected relevant data between issues in Korean documents and issues in English documents, Korean and English documents were analyzed and presented. The collected documents on blockchain technology which were mostly on the documents written in Korean were those published mostly in 2018; the documents written in English were mostly from 2017 and 2018, mostly addressing health issues. In the topic model, it can be judged that the topic of the English document is more appropriately classified than the Korean document. 

Abstract ················································································································1

Ch 1. Introduction ···························································································7

Ch 2. Blockchain Technology and Its Uses ···················································13

   A. What Is Blockchain ····················································································15

   B. Types and Uses of Blockchains ······································································31

   C. Limits of Blockchain ·················································································51

Ch 3. Document Based Analysis ·······························································55

   A. Processing Stopwords and Analyzing Morphemes ·································································57

   B. Text Quantification ··················································59

   C. Word Embedding Method ·················67

   D. Method of Data Analysis ··················································································72

Ch 4. Health and Welfare, and Blockchain Keyword Analysis ··········································77

   A. Text Collection and Data Processing ····································································79

   B. Refining Texts and Visualizing the Results ························································82

   C. Results of Korean Text Analysis ·············································································84

   D. Results of American Text Analysis ·············································································93

Ch 5. Conclusion ·······················································································101

References ···························································································107

Appendices ··································································································111