## 3 Research Method  
### Data Preparation  
The Privacy Act in the United States takes different approaches to the public sector and the private, unlike other regions such as Europe. This sectoral approach has the advantage that the law can promptly respond to new social issues and IT. Online privacy invasion factors vary by environment, so this study selected the legal precedents of the United States, which adopted a sectoral approach as the target of analysis. Therefore, this study analyzed United States judicial cases, which were collected from Westlaw database. Westlaw is a database that contains legal documentary data in the U.S. It classifies data based on key issues of judgments ([PERSON] et al., 2018). Among various classification items, this study collected 1098 cases of legal precedents (from January 2000 to December 2018) to obtain judgment documents related to privacy invasions. We collected data from Westlaw, which include only federal law precedents among numerous online privacy invasions across the United States. A federal law is applied to the nation as a whole and to all 50 states, whereas state laws are only in effect within that particular state. Therefore, in this study, only the precedents that have been sentenced based on federal law were selected for analysis, as that can be applied equally to all states in the United States. The reason that only cases sentenced by federal law are selected for this study is that it focuses on online privacy invasions that occurred in a virtual online environment without physical territorial limitations. In other words, this study deals with cases sentenced by federal law, regulating without physical territorial restrictions to reflect the features of online spaces rather than dealing with sentences under state law, including the regional characteristics in which the case occurred. Therefore, it is expected that the results of this study can be applied to online privacy infringement cases occurring across the United States without distinction of state law. Table 1 shows the numbers of the legal precedents each year we collected from Westlaw. The highest number of sentences related to online privacy invasions were decided under federal law in 2012 with 87, followed by 83 in 2018. To examine the interconnectivity between the words extracted from text preprocessing and judgments related to privacy invasion, they were classified into two groups as follows. First, actual malicious codes generated to collect personal data from other PCs without the users' consents are classified as \"type of privacy invasion\". Second, words relevant to the actual adjudication of precedents are classified as \"type of privacy invasion judgment\". The authors classified those words into 2 categories according to the research's main objective. For example, \"type of privacy invasion\" mainly consists of techniques that hold possibilities of privacy threats. The case of \"type of privacy invasion judgment\" is composed of terminology (i.e., conviction, compensation, innocence) that is usually used in verdicts for presenting the results of litigations. Table 2 shows that words are finally extracted to construct networks and provide meaning. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Year** & **Precedents** & **Year** & **Precedents** & **Year** & **Precedents** & **Year** & **Precedents** \\ \hline
2000 & 42 & 2005 & 41 & 2010 & 51 & 2015 & 51 \\ \hline
2001 & 53 & 2006 & 54 & 2011 & 53 & 2016 & 56 \\ \hline
2002 & 62 & 2007 & 44 & 2012 & 87 & 2017 & 77 \\ \hline
2003 & 61 & 2008 & 74 & 2013 & 56 & 2018 & 83 \\ \hline
2004 & 52 & 2009 & 49 & 2014 & 62 & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The Numbers of Precedents of Each Year. Types of privacy invasion judgments include conviction and innocence representing adjudication in terms of criminal law, and imprisonment, penalty, and probation, which are criminal punishments.