Expert system is a method used to implement human science to computer systems with the aim of solving a problem in the field of knowledge. Allergic disease is an overreaction from the body to certain particles from outside that enter the body which makes people feel uncomfortable and disturbed, allergies can occur with a variety of symptoms, some have experienced mild symptoms such as itchy eyes, sneezing, or reddened skin, and some are suffering from allergies with severe asthma. Factors from the causes of this allergy are very much encountered such as through the respiratory tract, through food, through drugs and so forth. Medical experts can use the application that has been built, which aims to make it easier to diagnose allergic diseases of the skin by only paying attention to the symptoms experienced. By using the Certainty Factor (CF) method, we get the value of a person's likelihood of developing allergic disease or not. The Certainty Factor (CF) method is very beneficial for the allergic skin disease system. Keywords: 3-5 Expert Systems, Skinpox, Certainty Factor.

In the current era of globalization, the development of computers in the health sector has become increasingly rapid. Computerized systems are needed especially in handling a disease. Because sometimes doctors, nurses find it difficult to know the type of illness suffered by adults, children and the elderly without a good computerized system. Abdominal colic, for example. Abdominal colic is a disease where there is an unpleasant feeling in the oral cavity between the thigh border and the chest rib border. This disease is caused by several factors, for example, eating is already full, eating a lot of acid, spicy and also drinking lots of alcohol. And usually occurs in adults. Where symptoms are symptoms such as nausea, vomiting and noisy intestines and excessive farts. With these symptoms, which becomes a control that a person has abdominal colic disease. Therefore the author made a study of the implementation of the HB rule on the diagnosis of abdominal colic disease. Theebb rule algorithm is a simple and uncomplicated learning method in the process, with the aim of minimizing the risk of disease problems that occur in patients, especially adults

The development of the modern era has made many people more influenced in using foreign languages in their daily lives. Almost every day, the people especially the generation in this era understand more about the use of foreign languages than the language from their own country. One of the efforts to strengthen the position of Indonesian is carried out by the Balai Balai Bahasa by developing an Indonesian language proficiency test tool called the Indonesian Language Proficiency Test (UKBI). The Indonesian Language Proficiency Test (UKBI) was assessed based on several factors of the participant's ability to listen, respond to the rules, read, write and speak. So far some of the UKBI participants at the North Sumatra Language Center have failed or failed, one of the contributing factors is that the assessment was not fulfilled. To overcome the problems above, a method is needed. The technique that can be utilized in the process of processing data is the classification with the C5.0 algorithm. C5.0 algorithm is a classification algorithm applied to decision tree techniques that are processed using information gain. In selecting attributes for object breakers in several classes, the attribute that produces the greatest information gain with the highest information gain value will be chosen as the parent of the next node.Keywords: Indonesian Language Proficiency Test, C5.0 Algorithm

Education is a very important thing and will continue to grow as time goes by, in Indonesia it is rather difficult to keep up with that development. In an effort to provide quality education in a school institution, it is necessary to attract students in choosing the best department in the school. The purpose of this student's specialization in the selection of majors is very important in supporting the knowledge of higher education and the enthusiasm of these students in developing knowledge in the chosen field, such as problems that have occurred in Lolowa'u N 1 Vocational School where students choose majors in accordance with people's encouragement others without any interest in the department, resulting in a decrease in enthusiasm for learning. Therefore, the grouping of students 'data in each department is done and grouped by value, because from this value can be seen the students' enthusiasm for learning. . Data mining is one way to convert data into useful information and can produce new knowledge. The method used is clustering, this clustering method is a method of grouping data. The results obtained in this study are the results of grouping data based on values and can be determined by interested students.

Operations Research is one way of taking decisions in companies by formulating problems of daily life with mathematical models with the aim of getting optimal goals. Transportation problems are one of the problems in solving operational research problems with the aim of optimizing distribution costs of shipping goods from the first warehouse to the destination warehouse. Like the problem that is in cv. Express nias where the cost of shipping goods does not calculate the optimal cost sometimes losses and profits are not optimal. The method used in solving this problem is the method of Vernel's approximation method, this method is included with the method of transportation. The results obtained in this study are that all shipping costs for cv.express nias are optimal.