The medical environment has been changed rapidly due to the advancement of science and medical technology, the increased demand of medical consumers, the strengthened evaluation of medical institutes, the opening of medical market, etc.. In this rapidly-changing medical environment, those medical institutes are making a lot of efforts to strengthen global competitiveness with higher quality medical environment and treatments system through the certification of JCI (The Joint Commission International) in addition to the evaluation of domestic medical institutes. One of the most essential strategies for strengthening the competitiveness of medical institutes is to utilize human resources of an organization as competitive resource. It is imperative for all nurses to have power and ability to lead an organization as a specialized nurse in order for an nurse organization to survive and succeed as competitive human resource in the fast-changing 21st century (Seong-Hee Park et al., 2006).

There is a growing interest in servant leadership in recent years; thus, the studies on servant leadership have become one of the major study areas for leadership. In particular, servant based service attitude is being emphasized at various levels from top management to nurses especially at such organizations as nursing organization that typically places importance on customer service. An emphasis is placed on forming a sense of sympathy based on unity by observing the positions and thinking of members carefully and achieving organizational objectives through voluntary service led by leaders rather than strong charismatic leadership with focus on work. As a result, servant leadership is gaining more attention (Daft, 2008; Young Yoon Kang, 2009). However, the previous studies on leadership in the nursing field have mainly focused on the leadership of head nurses and the work satisfaction of nurses. A majority of these studies have shown that the leadership type of head nurses have had a significant impact on the work satisfaction of nurses (Myeong Sook Kim, Young Bae Park, 2001; Soon Ja Choi, 2003; Hebert, 2003; Jung Hee Kim, 2006; Hyun Woo Jung, 2007). Therefore, an adequate level of leadership of head nurses or nurse managers can help form an atmosphere that allows nurses to perform nursing task properly and also to increase the morale of staffs in order to improve the performance of nursing task (Il Kwon Kim, 2005). Moreover, it will have a significant impact on the qualitative enhancement of nursing task and the goal attainment of nursing organization. Nursing definitely requires cooperation with superiors and colleagues in order to perform relevant tasks efficiently since nursing tasks should be performed in team and various nursing are related to each other given the nature of nursing tasks (Young Hee Kim, 2004; Neill & Saunders, 2008; Garber, 2009). In the end, this study found that effective leadership type was the driving force of qualitative improvement in nursing service and productivity of nursing organization by increasing the positive thinking of nurses and organizational commitment (Young Mi Hwang, 2000).

Head nurses are a front-line manager of a nursing organization and also an operator in the unit of nursing. Thus, they are the most essential intermediary manager within a nursing organization and also a supervising manager of ward nursing task who has an authority on all the phases of nursing activity within the objectives and system of hospital and nursing department and an authority and responsibility of instructing, adjusting and assessing the activities performed by all staffs within ward (Hyun Joo Baek, 2004). Head nurses may have a very important impact on the overall efficiency of a hospital and the enhancement of nursing quality provided to patients. That is to say, if head nurses have kind and warm attitude, interest and understanding and also competent leadership for fairness and care on nurses, then they will help nurses form a good relationship with each other and will have a positive impact on work satisfaction. Furthermore, they will have a huge contribution to the performance of high quality nursing. Thus, they can help nurses achieve their nursing goals and develop their potential ability (Jae Yeon Yoo, 2005). Such leadership of head nurses increases the morale of staffs by forming an adequate atmosphere to allow general nurses within the nursing unit to perform their role properly. Moreover, it has a significant impact on the occupational satisfaction and self-realization through job and also it is closely related to the organization commitment of nurses (Sung Sook Hahn et al., 2006; Mi Young Sim, 2005). The previous studies have shown that leadership with positive emotion had a significant impact on work satisfaction (Myung Hwa Kim, 2005) and organizational commitment and nurses had a higher degree of organizational commitment with higher emotional quotient (Hyun Woo Jung, 2007). Also, these previous studies have demonstrated that staffs evaluated organizational objectives and values positively and felt a sense of belonging and loyalty to enhance their organizational commitment when the emotionally sympathized values of staffs and organizational leaders were matched (Myung Hwa Kim, 2008). It would be required for an intermediary manager to play an effective role of leader in order to make organizational members demonstrate a sense of cooperation and commit to task with positive thinking since an intermediary manager should take a leading role of responding to changes proactively through motivating organizational members.

On that account, this study was conducted to provide preliminary data for enhancing organizational commitment by improving the servant leadership of an intermediary manager or head nurse and increasing the positive thinking of nurses within a nursing organization in the fast-changing hospital environment.

The purpose of this study is to identify the relationship between the servant leadership of nurse managers and the positive thinking of nurses and the organizational commitment. The specific objectives thereof are as follows.

1) To identify the general attributes of nurses

2) To analyze the difference between the servant leadership of nurse managers and the positive thinking of nurses and the degree of organizational commitment

3) To identify the correlation between the servant leadership of nurse managers and the positive thinking of nurses and the degree of organizational commitment 4) To identify the impact of the servant leadership of nurse managers and the positive thinking of nurses on the organizational commitment

1) Nurse Manager’s

Nurse managers refer to a person who manages nurses who perform on-site tasks across all departments of an organization. In this study, they refer to a head nurse who performs the role of a supervisor in the nursing unit of an actual work site.

2) Servant Leadership

Servant leadership means leadership as a helper. It refers to the leadership that helps members grow and helps a department or organization form a true community by respecting subordinates and providing them an opportunity to demonstrate their creativeness (Young Hee Lee, 2008). In this study, it means the score measured by the tool modified and complemented by Young Hee Lee (2008) based on SOLA (Servant Organizational Leadership Assessment) developed by Laub (1999).

3) Positive Thinking

Positive thinking is the way of thinking that their respective organization can resolve limitations and obstacles that might take place while performing tasks. It is also a positive expectation as to the problem-resolving ability of an organization (Lee,2008). In this study, it refers to the score measured by the tool that was modified and complemented by Eun Jung Tak (2010) based on the tool that used Automatic Thoughts Questionnaire-Positive developed by Ingram & Wisnicki (1988).

4) Organizational Commitment

Organizational commitment means strong trust, acceptance, intention to work for an organization and strong willingness to remain as an organizational member as to the objectives and values pursued by an organization. Thus, it refers to kinship, commitment, unity and attachment for one's respective organization (Mowday, Poter & Steers, 1979). In this study, it refers to the score measured after correcting the vocabularies for the hospital situations and nurses with the organizational commitment tool translated by Kim (2005) based on the organizational commitment measuring instrument developed by Mowday, Steers and Porter (1979).

The concept of servant leadership was first introduced in "The servant as a leader" of Greenleaf (1970). It was theoretically established after Spear (1995) proposed it. The etymology thereof is the concept that integrates servant and leader. Thus, it indicates the leadership of service attitude that serves subordinates as a servant. The leadership of nurses have been previously regarded as the attribute of a manager a nursing unit such as head nurse. Therefore, those studies on leadership have mainly focused on the leadership type of nurse managers and the influence hereof. It has been reported that the transformative leadership of nurse managers would affect the work commitment of nurses and increase the performance of nursing task. Moreover, the leadership type of head nurses would have more impact on the work satisfaction of nurses when it pursued human relationship more (Soon Min and Hye Sook Kim, 2005). However, it would not be enough for a leader alone to have leadership attributes and develop styles accordingly in order for an organization or group to have an outcome. Most of all, those organizational members such as general nurses should be motivated to work hard and voluntarily. It is required for a nursing organization to have an interest in the leadership of general nurses as a measure to strengthen the nursing ability of nurses and make general nurses become a professional nurse with positive attitude in the fast-changing social and competitive environment. The leadership of nurses is to allow nurses to have what they desire to have by helping them obtain what they want to have. Such leadership is the leadership that influences others while serving them. It encourages individual's growth and also attempts an qualitative improvement of an organization. It is also the servant leadership that provides supports and services while nurses trust each other (Hee Kyung Kim and Myung Soon Kwak, 2006).

As for the domestic researches, the study of Eun Joo Yoo (2008) on the relationship between servant leadership of nurse managers, trust as to superiors and organizational citizen behaviors recognized by the general nurses showed that the servant leadership of nurse managers, the trust of general nurses as to superiors and organizational citizen behaviors had a significant correlation. The study of Young Yoon Kang (2009) on the effect of servant leadership of nurse managers on the organizational effectiveness reported that servant leadership was one of the major factors to influence the organizational commitment, work satisfaction and organizational citizen behaviors of nurses. He emphasized that nurses were an essential part of hospital medical service; thus, nurses should understand the needs of subjects from the perspective of customers and provide professional information. To provide the pledged nursing services, it would be necessary to enhance servant leadership in the field of nursing. Myung Hee Sohn (2011) argued that the servant leadership of nurse managers at the small and medium-sized hospitals were the significant factor on both work satisfaction and organizational commitment of nurses. The study of Sang Sook Hahn and Nam Eun Kim (2012) confirmed the effect of servant leadership through the mediating variables since the leader effect, leader satisfaction and additional efforts of servant leadership had a positive impact on performance variables through the mediating variables of leader confidence and value conformity in the study on the impact of servant leadership of a leader, which was recognized by nurses on leader effect, leader satisfaction and additional efforts.

As such, leadership is an essential competency that nurses should have in order to provide professional services. It is also an important predicting factor that influences organizational effectiveness, nursing task performance and nursing service such as organizational commitment and work satisfaction. On that account, it is believed that each individual nurse, nursing organizations and hospitals should make a lot of efforts to support and manage leadership since the influencing factors on the leadership of nurses have been revealed through the studies on the leadership that nurses should have.

Recently, there is a growing interest in positive thinking rather than negative thinking in psychology (Seligman 2000). Positive thinking is understood differently than optimism. Optimism is more about simply expecting to have a good result in the future, whereas positive thinking is the state of a person in the course of decision-making or action. Positive thinking could overcome negative aspects resulting from a particular decision-making or judgment (Scheier and Carver1992; Taylor and Brown 1988). In other words, optimism is an attitude of expecting as to the desired state of each individual; thus, it tends not to think about negative incidents that might take place in the future. In contrast, positive thinking tends to overcome negative incidents that might take place in the future. Positive thinking used in this study is the same concept of positive thinking defined by Hyun Jung Kim et al. (2006), which was "to have positive awareness for oneself and one's life and accept it satisfactorily and find good aspects as to negative incidents and obstacles and leverage them as an opportunity of growth to pursue one's goals". Moreover, those people with positive thinking have stable state at present. They also tend to interpret or evaluate future events positively. That is to say, they tend to neglect negative events that will likely take place or they do not think of them at all (Scheier and Carver 1992; Seligman 2000; Taylor and Brown1988).

As for the domestic studies, Mi Young Park and Wan Il Kim (2014) examined the impact of positive thinking on the adaptation into military life. As a result, they found that those soldiers responding positively to a given environment and having positive view on the future could adapt into military life better. Kyung Ae Cha (2007) argued that the most influential variable on the adaptation into school life among the middle school students was positive thinking. Hye Sook Sim and Kyung Jin Hwang (2013) reported that self-control ability and positive thinking had a huge impact on the school life adaptation of middle school students. Summarizing the previous studies, people with a higher degree of positive thinking could adapt better into school life and military life. Also, it could be deducted that positive thinking was an important variable. As proved in the previous studies, positive thinking is significantly correlated to work life. Therefore, dissatisfaction with work due to a lack of positive thinking could lead to such negative outcomes as moving to another company and increased rate of work absence. So, it can be deemed important for the development and maintenance of a nursing organization. It is imperative to share professional information among treatment teams with positive thinking in order to provide high-quality nursing services and also conduct nursing tasks efficiently. Thus, it is believed that it will be necessary to conduct a follow-up study on nursing since there has not been any study on the positive thinking of nurses.

Organizational commitment is about kinship, commitment, unity and attachment for one's organization. Thus, it refers to the strong confidence as to the objectives or values pursued by an organization and the intention to work hard for an organization and the strong intention of remaining as an organizational members (Mowday, 1979). Organizational commitment refers to the degree of commitment and unity with one's organization, in other words, the relative degree of kinship and commitment of individuals as to their respective organization (Young Yoon Kang, 2009). Jung Hee Shin (2009) defined organizational commitment as relationship with an organization for organizational members to contribute actively to an organizational growth beyond their passive loyalty for their organization. Organizational commitment has been utilized in analyzing the interaction of individuals and organizations in relation to the organizational culture. Thus, it is an index to represent the turnover rate, work absence, performance and organizational effectiveness of staffs. It is widely used in many organizations since it is relatively long-term and stable in terms of representing the relationship between the attitude and behavior of organizational members (Kyung Ok Song, 2006)

Sang Sook Hahn (2009) argued that organizational commitment represented net correlation with the occupation value and interpersonal relationship preference of nurses. She also argued that it would enhance the performance of individuals and nursing and would lower the work-related stress, turnover rate and absence rate of nurses. Eun Joo Lee and Kwang Jeom Kim (2006) confirmed that servant leadership had a positive impact on organizational commitment.

This study is the descriptive survey research to identify the relationship between the servant leadership of nurse managers, the positive thinking of nurses and organizational commitment. The study subjects were the 150 nurses working at the university hospital and general hospitals in Cheongchung region, who had worked for more than 6 months and understood the purpose of the study and gave their consent hereto. A total of 150 questionnaires were distributed. A total of 120 (80 percent) copies were utilized for the final analysis after excluding the 30 incomplete responses.

The data collection was conducted from May 1 to September 30 2013. As for the survey contents, the survey investigated the general attributes and servant leadership, positive thinking and organizational commitment of the subjects. The general attributes included age, education, marital status, income, hospital size, etc. Servant leadership was Cronbach's ɑ 0.960. As for positive thinking, this study utilized the 11 questions from the tool modified and complemented by Tag (2010) based on the tool used by Kim et al. (2006) for general public, which was the modified and translated version of Automatic Thoughts Questionnaire-Positive developed by Ingram & Wisnicki (1988). In this study, Cronbach's Alpha value was 0.910. As for organizational commitment, this study utilized the 4 questions after excluding those items whose inter-index correlated factor loading value was 0.4 or less in relation to the items of each factor after correcting and verifying the vocabularies so that they would be suitable for the hospital situations and nurses based on the OCQ (organizational commitment questionnaire) developed by Steers & Porter (1982). In this study, Cronbach's Alpha value was 0.871.

As for the data analysis, this study processed computational statistics using SPSS/WIN15.0 statistical program. The results thereof are as follows.

1) This study analyzed the general attributes of subjects through real number, percentage, mean and standard deviation.

2) This study analyzed the degree of positive thinking and organizational commitment through mean and standard deviation.

3) This study analyzed the relationship between servant leadership, positive thinking and organizational commitment through Pearson Correlation Coefficient.

4) This study analyzed the difference in servant leadership, positive thinking and organizational commitment in accordance with the general attributes of subjects through t-test and ANOVA.

5) This study conducted multiple comparative analysis of Scheffe for post-verification.

6) This study conducted regression analysis as to the factors influencing servant leadership, positive thinking and organizational commitment.

In regard to the general attributes of nurses, the age group of 29 year old or younger accounted for 39.8 percent, whereas the age group of 30 to 39 year old accounted for 33.3 percent and the age group of 40 year old or older accounted for 26.9 percent. As for marital status, the unmarried nurses accounted for 47.4 percent, whereas the married nurses accounted for 52.6 percent. As for education level, those with graduate degree or higher accounted for 10.3 percent, whereas those with university degree accounted for 33.6 percent, those with college degree accounted for 50.5 percent and others accounted for 5.6 percent. As for number of work years, those with work experience of 3 years or less accounted for 32.3 percent, whereas those with work experience of 4 to 9 years accounted for 35.5 percent and those with work experience of 10 years or more accounted for 32.3 percent. As for income level, those with annual income of KRW 50 million or more accounted for accounted for 17.9 percent, whereas those with annual income between KRW 40.01 million and KRW 50 million accounted for 18.8 percent, those with annual income between KRW 30.01 million and KRW 40 million accounted for 29.5 percent, those with annual income between KRW 20.01 million and KRW 30 million accounted for 32.1 percent and those with annual income of KRW 20 or less accounted for 1.8 percent. As for type of medical institute, those working at university hospital accounted for 85.8 percent, whereas those working at general hospital accounted for 14.2 percent.