There are still many people who are less concerned with environmental cleanliness, where this can lead to the accumulation of bad bacteria that cause disease. One of them is Leptospirosis, a disease caused by a bacterial infection, namely the Leptospira strain. Leptospirosis is a disease caused by the laying of bacteria in animals that is transmitted to humans. This disease is often ignored by the public due to lack of understanding about this disease and the high cost of conducting examinations and consulting a doctor or hospital. So that in overcoming this we need a way that is able to help the community in knowing and diagnosing Leptospirosis, one of which is by using an expert system. The expert system used in solving the problem of Leptospirosis is by using the Naïve Bayes method. The application of the Naïve Bayes method in diagnosing Leptospirosis is carried out by collecting data about Leptospirosis where this process aims to find out what symptoms are caused by Leptospirosis. The process of collecting data on this disease is done by interviewing an expert or doctor who handles the problem of Leptospirosis. The results of the diagnosis of Leptospirosis based on the calculation of the Naïve Bayes method with new user data samples get results with a definite level of accuracy where the user experiences Leptospirosis disease with mild symptoms of 63% and the results of the user experiencing Leptospirosis disease with severe symptoms of 37%. Naïve Bayes is able to diagnose with 100% accuracy seen from the total severe and mild symptoms

The system is an attempt to assist in detection using sensors, an effort made for a room or house if people come or enter. A tool is designed that can be easy, affordable and can be used to prevent the danger of unknown people from entering the room or even into our homes. The author designed a "Smart Security" Room Security Detection System Using the Fuzzy Logic Method Using Internet of Things (IoT)-Based PIR Sensors. sending messages if someone enters the room or house so that the owner knows if someone is unknown. The author wants to design and make this tool that can be very helpful for use inside or at home in order to minimize the danger of people who cannot be recognized entering, room security detectors here with a distance of 1 cm to 2 meters the sensor can still be detected, if it exceeds 2 meter then the sensor will not read if anyone comes.

An effective sales system in a company requires an innovation and novelty in building a system that can help companies reach all market segments and society. Because the company's business activities still apply offline sales methods, namely coming directly to the store, viewing products and paying in cash. To meet the needs of the company and its customers, this company requires a web-based or online system for sales and customer data storage purposes. The programming language used is the PHP language using the CodeIgniter framework and MySQL as the database. The results of the research and the results of the output of this system will produce a website-based information system for selling jackets or clothes that can be used by the company or jacket shop to meet the needs of selling Hoodie Jackets from every consumer quickly and accurately, and is expected to assist in perform category searches by size, product orders, and digital payments for products.