The Effect of School Culture, Horizontal Communication, Knowledge Management, and Work Motivation of State Junior High Schools Teacher Performance in Medan

This study aims to investigate the effect of school culture, horizontal communication, management knowledge, and work motivation on teacher performance. The population in this study is 237 mathematics teachers in state junior high school and the sample consisted of 149 teachers. The results show that: school culture affects work motivation with a path coefficient of 0.318, horizontal communication influences work motivation with a path coefficient of 0.422, knowledge management affects work motivation with path coefficients of 0.233, school culture influences teacher performance with a path coefficient of 0.238, horizontal communication influences teacher performance with a path coefficient of 0.315, knowledge management affects the performance of teachers with a path coefficient of 0.169, and work motivation affects the performance of teachers with a path coefficient of 0.306. Based on these findings, it can be concluded that the strengthening of school culture, horizontal communication, and management knowledge causes higher work motivation which make performance better.


INTRODUCTION
In carrying out of organization, teacher has an important role for the effectiveness of an organization, especially in schools. A teacher is now required to have a dynamic mindset and behavior in line with the development of knowledge and technology. School is a small community that is very important to contribute to the advancement of schools in general in order to achieve the expected education. Good performance will produce good goals as well. Teacher performance in an organization is highly prioritized, for the sake of creating a conducive atmosphere for the progress of school organizations.
Good performance can benefit all members of the organization. Performance can be interpreted as an effort to gather strength to complete work in the organization to obtain maximum results Teachers in carrying out their tasks really need to be considered and evaluated their performance, because they have professional assignments which means it can only be done with specific competencies obtained through educational programs. Teacher performance is the ability shown by the teacher in carrying out the task or work. Based on these things, a teacher must be able to sort and choose when to empathize with students, when it is critical, when to accept or reject. In other words, a teacher must be able to play a dual role. This dual role can be realized differently according to the situation and conditions. The quality of education in State Junior High Schools in Medan is still considered low because graduates are not yet ready to enter further education due to the lack of competencies. The skills acquired in educational institutions are not sufficient to be used independently, it only transfers of knowledge which results students are not innovative, creative or even good at dealing with issues around their environment. The lack of competence and skills possessed by teachers affect the quality of teacher performance in learning. Teachers are less creative and innovative so that it is boring for students to obtain knowledge from teachers, because teacher performance is still at low levels.
Based on interviews with several school principals, August 23, 2018, it is concluded that there are problems with teacher performance. Many teachers still do not have high performance. There are still some teachers in teaching still using conventional approaches. They do not use methods that make students active. As a result, teaching process is not optimal in carrying out their assignments both in the classroom and outside the classroom. The effect of low teacher performance affects the student's learning achievement. The energy factor of the principal will be able to reduce the enthusiasm and work ability of teachers and this is very influential on the duty that is so much charged to teachers.
Based on observations in some state junior high school, there are still many teachers who have attitudes, values and ethics that are not in line with expectations. This is proven by the fact that there are still many teachers who do not carry out their tasks as they should. They are not punctual in the teaching-learning process in the class, postpone the implementation of the teaching-learning process, prioritizing additional tasks rather than their main duties as teachers. It can reduce the quality teacher's work. Although most of them have educator certificates, but their performance, productivity, work performance, work effectiveness is still not optimal. Furthermore, the relationship among of the teachers deals with kinship, family relations that work together in discussing methods of learning in the classroom or other problems. This is evidenced by the rarely occurring communication among teachers in discussions involving learning in class. Teachers must communicate with one another. They should become more solid and united, in carrying out the process of teaching students. It makes teacher to have more abilities, mastery, and skill. This view is similar to that expressed by Beaven (2003:88) that a teacher must exchange ideas with other teachers. Indrafachrudi (2000:52) describes two categories which influence the performance namely: Internal factors and external factors. Internal factors are factors that originate from within a person that can affect one's performance in carrying out their work, they are motivation and interests, talents, character, traits, age, gender, education, and experience, while external factors are factors that come from outside oneself that can affect their performance such as physical environment, facilities and infrastructure, benefits, atmosphere, policies, administrative systems and so on. Internal factors are work motivation, both individually and as an institution as a professional entity that requires awareness, and stronger responsibilities in carrying out their roles and functions as a teacher.
Work motivation is an important personality characteristic in an organizational environment. It is characterized by the encouragement of individual to excel others in accordance with a set of applicable standards and strive for success. Motivation is a commodity that needed by everyone including teachers. Teachers will work better if they are truly motivated. Teachers who have high work motivation will make a valuable contribution to education. The strength or weakness of work motivation depends on the amount of expectations to be achieved, the strength of the basis that gives rise to motivation and the amount of satisfaction obtained. People who have high work needs are happy to assume responsibility, like challenging work, have competition, be proud of their work and confident in their abilities. Mohammed and Doghan's research (2015) shows that there is a direct relationship between work motivation and performance. Teachers will work better if they are truly motivated. Teachers who succeed because of work motivation will make a valuable contribution to education.
Knowledge management is also as important as work motivation which can improve teacher performance. Teachers need knowledge because they are faced with a variety of activities that involve a lot of interaction with others, so it is needed. Educational management refers to the process of planning, organizing, directing, and controlling educational resources to achieve educational goals effectively and efficiently. Thus, knowledge management describes cognitive abilities in the process of planning, organizing, directing, and controlling educational resources to achieve educational goals effectively and efficiently.
Furthermore, the variables that affect teacher performance are horizontal communication. Horizontal communication is a variable that comes from outside a teacher. It determines teacher performance. Teachers who have the ability to communicate horizontally in carrying out their duties will realize that they have a great responsibility in achieving educational goals. Conversely, if a school principal does not have the ability to communicate horizontally with the teacher in carrying out their duties and obligations, it will have implications for the decline in teacher performance, even further will have an impact on the deteriorating quality of human resources.If horizontal communication among teachers is able to be synergized, it will have a positive impact on their performance. It encourages the enthusiasm of the teacher's work which in turn can spur their performance.
In line with Riyadi et al (2017), it is also known that communication influences work motivation and has an influence on teacher performance. There is an effect of communication on job satisfaction for lecturers, as well as an increase in motivation among lecturers, especially motivation in work. Professional lecturers who always perform well must be able to be maintained and improved by paying attention to the components that are motivated by their work so that their performance increases. In line with the research conducted by Wijaya and Herminingsih (2015), it is also known that communication influences motivation and has an influence on teacher performance. Organizational communication, work motivation and compensation together have positive and significant effects on teacher performance.
School culture is also thought to be worth investigating as a variable that can affect performance. Jumari et al (2013) reveals that there is a positive and significant influence of organizational culture on the teaching performance of teachers in Sate Vocational School South Denpasar with a determination of 39.6% and an effective contribution of 17.6%. Liana (2012) explains that there is a significant influence of organizational climate on teacher performance. School culture is the soul of a school that gives meaning to the educational activities of the school, if school culture is weak, and then it is not conducive to the formation of an effective school. Conversely a strong school culture is a facilitator for effective school improvement. School culture can influence several variables that can make schools effective and performance among teachers' increases namely work performance and motivation. If school culture is good, it is possible to increase work motivation which ultimately improves teacher performance. Colquit (2009) in Integrative Model of Organizational Motivation states that performance variables and motivational variables are directly influenced by organizational culture Based on the theories described above, it is necessary to conduct this research in order to solve the problem of teacher performance which has so far been ineffective at state junior high schools in Medan. The variables that Journal of Education and Practice www.iiste.org ISSN 2222-1735 (Paper) ISSN 2222-288X (Online) Vol.11, No.15, 2020 are considered the most dominant to solve the problems above are used as variables in this study, namely School Culture, Horizontal Communication, knowledge management, work motivation, and performance of teachers at state junior high schools in Medan.

LITERATURE REVIEW 2.1 Teachers Performance
The term teacher performance can be interpreted with work performance or actual achievement achieved by someone. National Education Department (2004:4) defines performance with work performance. Performance leads to an effort in order to achieve better work performance, other words performance is one's success in carrying out a job. According to Robbins (2009) performance is defined as what is done and what is not done by employees. Rivai (2006) states that performance is an achievement achieved by someone in carrying out their duties or work in accordance with the standards and criteria set for the job.
It is concluded that performance is an achievement produced by someone in the form of achievement in accordance with established standards. Operational performance of a teacher is an achievement produced by a teacher from achievement in accordance with established standards. This research uses an indicator of teacher performance which is measured through planning learning activities, implementing learning activities, and evaluating learning.

Work Motivation
Basically, someone works because of the desire to meet his life's needs. Motivation is an encouragement factor that can trigger a sense of enthusiasm and is also able to change the behavior of humans or individuals to lead to things that are better for themselves. According to Hasibuan, motivation comes from the Latin word movere which means encouragement or move. Sutrisno (2013:109) states that motivation is an actor who pushes someone to do a certain activity. It is often interpreted as a factor driving a person's behavior. Mangkunegara (2012:61) also states motivation is a condition or energy that moves employees who are directed to achieve organizational goals. Hamalik (2004: 173) explains motivation can be basic or internal impulses and intensive outside the individual or gift. While Nawawi (2003) states motivation is a condition that encourages or becomes a reason for someone to do an activity that takes place consciously, in order to achieve company goals. There are several objectives that can be obtained.
Based on some of the explanations above, it can be concluded that work motivation is a condition or force that drives a person to carry out certain activities in order to achieve a goal. Teacher's work motivation is the overall driving force within a teacher who is endeavored to guarantee the continuity of his work by giving direction so that the goals of work that have been formulated can be achieved. Indicators of teacher work motivation are: the desire to succeed, the encouragement and need to work, the appreciation of work, the existence of a conducive environment, and pleasant working conditions

Knowledge Management
Management can be defined as an effort to manage resources to achieve the expected goals. Humans need knowledge because they are faced with a variety of activities that involve a lot of interaction with others, so knowledge management is needed. Hasibuan (2011:1) Management is the science and art of regulating the process of utilizing human resources and other resources effectively and efficiently to achieve a certain goal. It is the control and utilization of all factors and resources that according to a plan are needed to achieve or complete a particular work goal.
In the world of education, management education plays a very important role. Basically management of learning is the regulation of all learning activities that are categorized in the core curriculum. In other words, Education Management is an activity or a series of activities in the form of a business management process in the collaboration of a group of people who are members of an educational organization, to achieve the educational goals that have been previously determined, to be effective and efficient. Siagian (2005:17) explains that the management function is planning, organizing, motivating, monitoring and evaluating. Furthermore, knowledge refers to everything that is known to individuals. Thus, knowledge management describes cognitive abilities in the process of planning, organizing, directing, and controlling educational resources to achieve educational goals effectively and efficiently. In accordance with its nature, knowledge is a cognitive ability related to affective abilities, and psychomotor abilities that individuals obtain through education. Sagala (2006:15) management principally carries out the functions of planning, implementation and control into a series of decision-making activities that are fundamental and comprehensive in the process of efficiently utilizing all resources accompanied by the determination of how to implement them by all levels in an organization to achieve organizational goals. Manullang (2004:10) states management is the art and science of planning, organizing, directing, coordinating and controlling to achieve predetermined goals.
From some of the explanations above, it can be concluded that knowledge management in this study is the

Figure 1 Research Variable Path Diagram
Statistical computation of correlation coefficients and path coefficients following testing are summarized in Table 1. In accordance with the path diagram of the research variables obtained based on the theory and the results of hypothesis testing, the relative influence of exogenous variables on endogenous variables. Based on the calculation results, a summary of the relative influence of school culture (X1), horizontal communication (X2), management knowledge (X3), and work motivation (X4) has a direct and positive effect on teacher performance (X5) as in Table  2 below. Journal of Education and Practice www.iiste.org ISSN 2222-1735 (Paper) ISSN 2222-288X (Online) Vol.11, No.15, 2020 (X2), knowledge management (X3) combined to work motivation (X4) ) is 64% while the remaining 36% is influenced by other factors. Furthermore, the coefficient of determination of Model II from the calculation results obtained by 74%, which means that the influence of school culture (X1), horizontal communication (X2), management knowledge (X3), and work motivation (X4) combined to Teacher Performance (X5) is 74 %, while the remaining 26% is influenced by other factors.

DISCUSSION
The results of this study partially indicate that the school culture variable (X1) has a direct positive effect on work motivation (X4) with the acquisition that p41 = 0.318 and significance > 0.05, it means that Ho is rejected or Ha accepted, so it can be concluded that school culture (X1) has a direct positive effect on work motivation (X4) of Medan state junior high school teachers. This implies an increase of 1 unit variable school culture increases the variable work motivation of teachers by 0.318 units assuming other variables are considered constant. In general, the work of teachers is divided into two, namely: related to teaching and educating tasks, as well as social tasks. As instructors, teachers provide knowledge (cognitive), attitudes and values and skills. Good and bad teacher performance is determined by various factors, including: organizational climate, achievement motivation and teacher job satisfaction (Falahi, 2005). Good school culture increases work motivation of teachers. School culture ultimately increases the work motivation of the teacher. Culture is a positive influence on the organization if it raises behavior in the right direction, widely permeating members of the organization to follow the applied culture. Furthermore culture negatively affects an organization if it results in behavior in the wrong direction.
The results of this study partially indicate that the horizontal communication variable (X2) has a direct positive effect on work motivation (X4) of teachers with the acquisition that p42 = 0.422 and significance > 0.05, it means that Ho is rejected or Ha is accepted, so it can be concluded that horizontal communication (X2) has a direct positive effect on work motivation (X4) of the teacher. This implies an increase of 1 unit variable Horizontal communication increases the teacher's work motivation variable by 0.422 units assuming other variables are considered constant.
The results of this study partially indicate that the variable Knowledge management (X3) has a direct positive effect on work motivation (X4) of Medan State Junior High School Teachers with the acquisition that p43 = 0.233 and significance > 0.05, it means that Ho is rejected. Thus, Ha is accepted. It can be concluded that Knowledge management (X3) has a direct positive effect on work motivation (X4) of Medan State Junior High Teachers. This implies an increase of one unit variable of Knowledge management increases the variable of work motivation of teachers by 0.233 units assuming other variables are considered constant.
The results of this study partially indicate that the school culture variable (X1) has a direct and positive effect on Teacher Performance (X5) of Medan state junior high school with the acquisition that p51 = 0.238 and significance > 0.05, it means that Ho is rejected or Ha is accepted, so it can be concluded that school culture (X1) has a direct and positive effect on Teacher Performance (X5). This implies an increase of 1 unit of school culture variables increases teacher Performance variable by 0.238 units assuming other variables are considered constant.
The results of this study partially indicate that the horizontal communication variable (X2) has a direct and positive effect on Teacher Performance (X5) of Medan City Middle School Teachers with the acquisition that p52 = 0.315 and significance > 0.05, it means that Ho is rejected or Ha is accepted, so it can be concluded that horizontal communication (X2) has a direct and positive effect on Teacher Performance (X5) of Medan state junior high school. This implies an increase of 1 unit variable Communication horizontally increases teacher Performance variable by 0.315 units assuming other variables are considered constant.
The results of this study partially indicate that the variable Knowledge management (X3) has a direct and positive effect on Teacher Performance (X5) of Medan state junior high school teachers with the acquisition that p53 = 0.169 and significance > 0.05, it means that Ho is rejected or Ha is accepted, so it can be concluded that Knowledge Management (X3) has a direct and positive effect on Teacher Performance (X5). This implies an increase of 1 unit of variable Management knowledge increases the teacher performance variable by 0.169 units assuming other variables are considered constant.
The results of this study partially show that work motivation (X4) has direct and positive influence on work Teacher Performance (X5) of Medan state junior high school with the acquisition that p54 = 0.306 and significance > 0.05, it means that Ho is rejected or Ha accepted, so it can be concluded that work motivation (X4) has a direct and positive effect on work motivation (X4) Teacher Performance (X5) at sate junior high school in Medan. This implies an increase of 1 unit of work motivation variable increases the teacher performance variable by 0.306 units assuming other variables are considered constant.
The results of this study are in accordance with the research of Mohammed and Doghan (2015). It shows that there is a direct relationship between work motivation and performance. Teachers works better if they are truly motivated. Teachers who succeed because of work motivation will make a valuable contribution to education. The strength or weakness of work motivation depends on the amount of expectations to be achieved. People who have high work needs are happy to assume responsibility, like challenging work, do not avoid competition, are proud of their work and confident in their abilities. This is also in line with research conducted by Zulkifli et al (2014) state that work motivation has a positive effect on teacher performance. Educational institutions that provide motivation to the teacher well will be followed by an increase in teacher performance. Motivation is the provision of movement that creates excitement to work so that someone is willing to work together, work effectively and be integrated with all their efforts.
Thus, the results of research through testing hypotheses that accept the seven proposed research hypotheses have found a new finding in the form of a fixed model or a theoretical model of teacher performance that describes the model as proposed in the Theoretic Model of Research Variables. Based on the results of testing the hypotheses that accept seven research hypotheses proposed as described above, a teacher performance model is developed, which is the development of several theories describing casuistic relationships between research variables that determine teacher performance which is the development of several theories, especially from Colquitt (Integrative Model of Organizational Behavior), LePine, and Wesson(An Organizational Behavioral System).
Based on the results of a theoretical study and the results of an analysis of the structure of associative causal relationships between exogenous variables and endogenous variables, the Performance Model of the teacher is perfectly fit with the data to be implemented adaptively in Medan sate junior high school as in Figure 2 below.

Figure 2 Teacher Performance Models and Affecting Factors
This study explains that improvement in teacher performance can be built through strengthening school culture, horizontal communication, management knowledge and work motivation which can be implemented adaptively at state junior high schools in Medan. Strengthening school culture, horizontal communication, knowledge management causes higher work motivation which in turn makes performance better.

CONCLUSION
Based on the foregoing descriptions and the results of data analysis and discussion of the results of research conducted, the teacher performance model is built based on the causal associative relationship among the exogenous variables of school culture, horizontal communication, management knowledge, and work motivation with endogenous variables of teacher performance. Teacher performance models of the findings of this study explain that improving teacher performance can be done in two ways, namely: through strengthening school culture, horizontal communication, management knowledge, and work motivation which directly cause teacher performance to be better. In addition, it can also be done through strengthening school culture, horizontal communication, and management knowledge which directly lead to increased work motivation which further enhances better teacher performance.