Introduction
 ... [1]. Block describes resilience as the ability to adapt the control level to environmental conditions [2]. Connor has defined resilience as a procedure to estimate a person's ability to cope with stressors and factors that threaten a person's mental health [3]. … [4, 5]. The role of personality traits is one of the issues in the field of resilience [6]. As a result, people respond differently to stress because their individual personality traits encourage different coping strategies. ... [7]. Studies that have examined the relationship between the five major personality factors and resilience are among the studies that have examined the role of personality traits in resilience. These studies are consistent with each other in several results. First, resilience has a significant negative relationship with neuroticism [8], In addition, most of these studies have shown that resilience has a significant positive relationship with extraversion [9]. ... [10]. The research of Joseph and Heyse points out that the strongest predictors of happiness, life satisfaction and mental well-being, among personality traits, are extraversion and conscientiousness which create a personality compatible with high mental well-being in work and social status and various environmental situations [11]. In the study of Sa'adat with the title of "The Relationship between Personality Traits and Resilience", the results indicated a significant negative relationship between neurosis and resilience and a significant positive relationship between extraversion, flexibility and responsibility with resilience, and there was no significant relationship between agreeableness and resilience.
Aim(s)
The aim of this study was to develop a resilience model based on personality traits mediated by perceived stress in military personnel in Tehran, Iran. (Figure 1).
Research Type
This research is a correlational type in the form of structural equation modeling.
Research Society, Place and Time
The population of the study was all employees of a military unit who were serving in Tehran, Iran in 2019.
Sampling Method and Number
The sample size was 367 people based on Morgan table who were selected by random cluster sampling.
Used Devices & Materials
… [12-15]. The Connor and Davidson Resilience, NEO Personality Inventory and Perceived Stress questionnaires were used to collect data. A study on the psychometric properties of the resilience scale in the general population and patients showed that the instrument has internal consistency, test-retest reliability, convergent and divergent validity. Mohammadi has standardized this scale for use in Iran. This reliability was obtained by measuring the internal consistency of Cronbach's alpha as 0.89. [2]. Cronbach's alpha coefficients of the Neo Personality Traits Questionnaire in Haghshenas research have been reported as C = 0.83, A = 0.71, O = 0.57, E = 0.71 and N=0.81. [16]. The internal consistency reliability coefficients of the perceived Stress scale were also obtained through Cronbach's alpha in the range of 0.84 to 0.86 [16].
Ethical Permissions
The objectives of the research and the work process were clarified for the participants in order to maintain the ethical standards in the research.
Statistical Analysis
Structural equation modeling was used to determine the fitness of the model and to estimate direct and indirect structural effect coefficients. Data were also analyzed using Lisrel 8.5 software.
Finding by Text
In the present study, all the participants were male. 324 questionnaires were well-completed to be evaluated. 46% (152 people) of the participants had high school diploma, 15.92% (50 people) with associate degree, 32.7% (106 people) had a bachelor's degree and 4.9% (16 people) had a master's degree or higher. Also, 29% were single (94 people) and 71% were married. In addition, 49.7% of the participants served as day shift and 50.3% as shifts of 24 hours a day. The resilience scale of the samples was 57.1±15.7. Table 1 shows the indicators related to descriptive statistics for the study sample, including the mean of the variables of the study. The fit indices of the initial model were evaluated. For fit indices, several sections have been proposed by experts, for example, a value equal to or less than 0.05 for the root of variance of the approximation error, a value equal to or greater than 0.96 with a comparative fit index, equal to or less than 0.07 for the standard root that is the residual variance that indicates the adequate fitness of the model. On the other hand, it has been suggested that if the comparative fit indices, goodness of fit and adjusted goodness of fit are greater than 0.90 and the root mean variance of the approximation error and the root of variance of the residual is less than 0.05, the fit is highly desirable and less than 0.1. Indicates a good fit. No parameter in the measurement models had a sign contrary to the theory (Table 2) and all three methods had a good fit. Some indicators indicated improper fit and in the models the measurement of some parameters was not significant. In the structural relationships of variables, non-significant indicators were removed. After modifying these indicators, the data with the new model had a good fit (Table 2). Finally, out of 30 personality traits in this study, 14 traits explained the resilience model based on personality traits (Figure 2). No parameter in the measurement models had a sign contrary to the theory (Table 2) and all three methods had a good fit. Some indicators indicated improper fit and in the models the measurement of some parameters was not significant. In the structural relationships of variables, non-significant indicators were removed. After modifying these indicators, the data with the new model had a good fit (Table 2). Finally, out of 30 personality traits in this study, 14 traits explained the resilience model based on personality traits (Figure 2).
Main Comparison to the Similar Studies
[17-23] Sa'adat in examining the relationship between personality traits and resilience has reported a significant negative relationship between neurosis and resilience and a significant positive relationship between extraversion, flexibility and responsibility with resilience and no significant relationship between agreeableness and resilience. Moharramzadeh et al. also studied the relationship between employees' personality traits and burnout in the Ministry of Sports and Youth. The results show that people with higher levels of neuroticism and lower levels of extraversion, agreeableness, conscientiousness and openness are more prone to burnout [2].
Examining the path of personality traits to perceived stress showed that personality traits had a direct structural effect on perceived stress. This finding is consistent with the results of Mirhaghi and Sarabian's research on the significant relationship between personality traits and perceived stress. These researchers point out that there is a significant positive relationship between some personality traits (neurosis) and perceived stress and a significant negative relationship between some personality traits (extraversion, conscientiousness, agreeableness, openness) and perceived stress. Consistent with this finding, we can refer to Ahmadi's research on the prediction of stress and burnout based on the personality traits of nurses. Findings show that neuroticism, agreeableness, conscientiousness, extraversion and flexibility predict job stress and burnout in nurses. Also in the research of Mir Hassani et al. regarding the mediating role of personality traits in relation to perceived stress and anxiety and depression and physical symptoms, the research findings indicate the relationship between perceived stress and neuroticism, extraversion and conscientiousness. In explaining this finding, it could be argued that according to the present exploratory model and the structural effect on perceived stress, these traits can be considered as predictors of perceived stress [13]. Examining the path of perceived stress to resilience showed that perceived stress had a direct structural effect on resilience. This finding is consistent with the results of Hosseini and Salimi's research. Pourafzal et al. also reported a significant negative relationship between resilience and perceived stress.
Suggestions
It is suggested that people with high resilience be selected as employees so that less personal and organizational harms occur and organizational productivity and dynamism increase, and to prevent the loss of manpower and financial capital.
Limitations
Conducting research in a specific group and not having female samples were of the limitations of this study.
Conclusions
Based on the explained model, the personality traits components are able to directly predict the changes of the resilience variable and indirectly through the perceived stress variable. According to the findings of this study, 14 out of 30 personality traits form the resilient model.
Clinical & Practical Tips in Police Medicine
Due to the need for resilient people in stressful jobs such as military occupations, this model can be used in recruiting and locating employees to prevent problems and issues related to employees such as mental disorders and occupational problems and harms and organizational challenges such as work productivity and human resource waste.
Acknowledgments
This article is taken from the doctoral dissertation approved in the spring of 2018 by the Islamic Azad University, Qom, Iran. We thank all the participants of the present study and those who helped us in this research.
Conflict of Interest
 The authors state that there is no conflict of interest in the present study.
Funding Sources
The present study had no financial support.

Table 1) Descriptive statistics of personality traits components

Figure 1) Conceptual model of research based on adjective theory


Figure 2) The final model of resilience based on personality traits mediated by perceptual stress (standard values)

Table 2) Fitness indices of the initial and final model (n=324)