# Activity Recommendation Model Using Rank Correlation for Chronic Stress Management
## 3 Activity Recommendation Model using Rank Correlation for Chronic Stress Management  
### Data Collection and Preprocessing  
Concerning chronic stress data, the raw data of mental health in National Health and Nutrition Survey [25] provided by Centers for Disease Control and Prevention under the Ministry of Health and Welfare is preprocessed before use. The raw data consist of 13,248 people in total, of which the data related to mental health are used. Children under the age of 12 are not eligible for collection of mental health data. Therefore, 6547 data were extracted form 13,248 people except for no response and children. The composition of the collected data is as follows. The sex ratio consists of 3665 men and 2882 women. Age for mental health collection ranges from 12 to 80. The age distribution is evenly distributed. There are 586 people over the age of 12 and under 20, 681 people over the age of 20 and under 30, 1039 people over the age of 30 and under 40, 1089 people over the age of 40 and under 50, 1052 people over the age of 50 and under 60, 1055 people over the age of 60 and under 70 and 1045 people over the age of 70 and under 80. Also, the income quartile is classified into lower, lower and middle, upper and middle, and upper. Preprocessed data were collected at lower quartiles of 1642, lower and middle 1644, upper and middle 1631, and upper 1630. Figure 4 shows a scatter plot of the stress levels of users in the preprocessed data. Figure 4: Scatter plot of the stress levels of users. It shows users' stress values depending on discrete values. The value 1 means 'hardly feel', the value 2 'a little feel', the value 3'much feel', and the value 4'very much feel'. Of 6547 persons, only 329 hardly felt stressed, 3680 much felt stressed, and 1087 very much felt stressed. In short, of 6547 persons, 4767 or 72.8% felt stressed much. It means that in today's society, most people are chronically stressed. By looking at the trend visually, it is possible to make an intuitive prediction. The collected mental health data consists of the result of conventional PSS (bPSS), Activity Information for Stress Management (AISM), the PSS result for activity (aPSS), and the difference between bPSS and aPSS. The AISM collected by medical information portal [26; 27] is comprised of Positive Activity for Stress Management (PASM) and Negative Activity for Stress Management (NASM). PASM means stress alleviation activities, including proper exercise (PASM\({}_{1}\)), leisure time (PASM\({}_{2}\)), rest time (PASM\({}_{3}\)), and healthy dietary habit (PASM\({}_{4}\)). NASM means the activities negative to stress alleviation, such as insufficient or excess exercise (NASM\({}_{1}\)), leisure time (NASM\({}_{2}\)), rest time (NASM\({}_{3}\)), and inappropriate dietary habits like drinking (NASM\({}_{4}\)). For one month, a user gives scores ranging from 1 to 5 to activities differently depending on the intensity and frequency of PASM\({}_{i}\) or NASM\({}_{j}\). The score '1' represents the lowest intensity and frequency of activity. The score '2' means a little lower intensity and frequency of activity. The score '3' means the intermediate intensity and frequency of activity. The score '4' means a little higher intensity and frequency of activity. The score '5' represents the highest intensity and frequency of activity. For instance, if the intensity of PASM\({}_{1}\) is 3, and its frequency is 5, it means that PASM\({}_{1}\) was executed with the intermediate intensity and the highest frequency. With the use of the mean of the PASM\({}_{i}\) and NASM\({}_{j}\), the PASM and NASM values per week are calculated. The difference between bPSS and aPSS means increased or decreased stress. A positive number of differences means less stress, and a negative number means more stress. Of the data, the example of one-week data is presented in Table 1. User1 scored 12 of bPSS, 8.35 of PASM, and 21.23 of NASM, and the user's aPSS changed to 18 after one month.