For a multi-attribute decision making (MADM) problem, the information of
alternatives under different attributes is given in the form of intuitionistic
fuzzy number(IFN). Intuitionistic fuzzy set (IFS) plays an important role in
dealing with un-certain and incomplete information. The similarity measure of
intuitionistic fuzzy sets (IFSs) has always been a research hotspot. A new
similarity measure of IFSs based on the projection technology and cosine
similarity measure, which con-siders the direction and length of IFSs at the
same time, is first proposed in this paper. The objective of the presented
pa-per is to develop a MADM method and medical diagnosis method under IFS using
the projection technology and cosine similarity measure. Some examples are used
to illustrate the comparison results of the proposed algorithm and some
exist-ing methods. The comparison result shows that the proposed algorithm is
effective and can identify the optimal scheme accurately. In medical diagnosis
area, it can be used to quickly diagnose disease. The proposed method enriches
the exist-ing similarity measure methods and it can be applied to not only
IFSs, but also other interval-valued intuitionistic fuzzy sets(IVIFSs) as well.

基于投影技术和余弦相似度测量的直觉模糊集相似度测量方法首次被提出，开发了一种基于该方法的多属性决策和医学诊断方法，与现有方法相比具有更高的准确性，在医学诊断领域具有快速诊断疾病的能力，可应用于直觉模糊集和区间价值直觉模糊集。