Referent Object: It is an object that is taken as the focus for analysis in security studies. As to this concept, there are two main approaches to the security: state-centric security (the state is the referent object) and human-centric approach (human is the referent object).

Traditional Security Studies: It refers to Realist, Liberal, Peace Studies and Strategic Studies perspectives in the study of security. All of them prioritize the state as the referent object of security and focus on military threats to the security of the state.

Broadening: The broadening security agenda refers to Barry Buzan’s sectoral analysis that the security agenda includes not only military sector issues but also political, economic, societal and environmental issues.

Deepening: The state is not only the referent object of security but it also includes human individuals, institutions and groups.

Positivism: It claims that social sciences can be built upon the same model as natural sciences. Scientific principles such as objectivity, verification/falsification, and generalization can adapt to the study of society.

Post-Positivism: It rejects the idea that it is possible to analyze the natural world and the social world in the same way. There is no objective view (Peoples and Vaughan-Williams, 2010:4).