An online marketplace site is a shopping place that is currently popular with the community because it offers a variety of convenience and one of the marketplace apps is Shopee. Some people are satisfied with the service provided by the Shopee app. But unisex some people who give complaints about this application. User-provided response to Shopee app in the Comments field of Shopee Google Play Store can be analyzed for negative and positive sentiments. This research aims to assist Shopee’s management of the positive or negative opinions of application users and can provide empirical evidence for related theories so that it can be used as a donation of thought for the development of theories Next. With the number of reviews shown, you need an analysis that can classify these reviews into positive or negative classes. The method used for the sentiment analysis of Shopee app reviews is the Naive Bayes algorithm obtaining an accuracy yield of 96,667%

The lack of knowledge about dental health and the still limited awareness of the community about dental health, makes some of our community set aside in efforts to prevent or treat dental disease. So we need a system or application that can help people to find out about dental diseases, as well as solutions to overcome these problems. This expert system knowledge base is formed by the if-then rules. The inference method used is forward chaining. This dental disease expert system is based on Android so it can be used anytime and anywhere by the community. Based on the acquisition of expert knowledge obtained 12 rules, 12 diseases, 25 symptoms. Blackbox test results show the application features that are made to run with a fairly good level of success. Unit test results indicate that the application has succeeded in making inferences properly and correctly, in accordance with applicable rules.Keywords: Dental disease, forward chaining, android, expert systemAbstrakMinimnya pengetahuan kesehatan gigi dan masih terbatasnya  kesadaran masyarakat tentang kesehatan gigi, membuat sebagian masyarakat kita mengesampingkan dalam upaya mencegah atau mengobati penyakit gigi. Maka diperlukan suatu sistem atau aplikasi yang dapat membantu masyarakat untuk mengetahui tentang penyakit gigi, serta solusi untuk mengatasi permasalahan tersebut. Basis pengetahuan sistem pakar ini dibentuk dengan aturan if-then. Metode inferensi yang digunakan adalah forward chaining. Sistem pakar penyakit gigi ini dibuat berbasis android agar bisa digunakan kapan saja dan dimana saja oleh masyarakat. Berdasarkan akusisi pengetahuan pakar didapat 12 aturan, 12 penyakit, 25 gejala. Hasil uji blackbox menunjukan fitur-fitur aplikasi yang dibuat berjalan dengan tingkat berhasilan yang cukup baik. Hasil pengujian unit menunjukkan bahwa aplikasi telah berhasil melakukan inferensi dengan baik dan benar, sesuai kaidah yang berlaku. Kata kunci : Penyakit gigi, forward chaining, android, sistem pakar

Hotel service website is currently growing very rapidly, along with the development of tourism worldwide. The progress of world-class tourism is influenced by the provision of the international class accommodation. Selecting hotels considers generally expensive facilities, services and other supporting infrastructure. Currently the hotel booking service providers already provide facilities for tourists to write reviews and experiences of staying in the hotel room for other travel recommendations. With so many reviews displayed, it is necessary to perform a classification analysis of the review into a positive or negative grade. The method used for sentiment analysis of the hotel review is Naive Bayes Algorithm and Particle Swarm Optimization, This research examined data from sentiment hotel reviews on several hotel booking websites of 100 positive reviews and 100 negative reviews. The resulting combining Naive Bayes with Particle Swarm Optimization and obtains the best value with accuracy of 85.00%.

The internet customer registration system currently running at PT. Kotadata Erasistema Nusantara is still done manually. In the registration process it is still used conventionally so that there are still many perceived shortcomings because the method using paper media is in the form of filling out forms manually by customers, so a Web-Based Internet Registration Information System is needed. The purpose of making this Web-Based Internet Registration Information System, among others, is that from the internal side it can facilitate management in making decisions and from the external side it can make it easier for internet customers to obtain information. The method used in making this Web-Based Internet Registration Information System uses an SDLC (System Development Life Cyce) development system using the waterfall process model. For the software development model used by the author in conducting this research using Model Programming (XP), Extreme Programming (XP). In making the application using the PHP programming language and the database used is the MySQL database. The results of this Web-Based Internet Registration Information System are in the form of a Registration System Application that can provide convenience in the customer registration process so that it is more effective and efficient in the process of collecting data on the number of subscribers who have subscribed and new subscribers who have subscribed

- In the current era of globalization, information technology is accelerating. The computer is an equipment created to facilitate human work, when achieving progress both in the manufacture of hardware and software. There are so many factories that are built in big cities and small towns and some are even in the middle of residential areas. Factory waste can cause a polluted environment including pollution in water that causes disease. For this reason, the author is trying to make the final project about the production of metal laying detectors on Arduino-Based Water UNO. This detector can detect metal levels in water, conductivity sensors will detect water and determine whether or not the water is based on the Regulation of the Minister of Health of the Republic of Indonesia number 492 of 2010 concerning the requirements of drinking water quality. This tool can make it easier for people to find out whether or not water is feasible in the environment.Keywords— Detectors, Metal Detectors on WaterAbstrak - Dalam era globalisasi sekarang ini, teknologi informasi melaju dengan cepatnya. Adapun computer yang merupakan peralatan yang diciptakan untuk mempermudah pekerjaan manusia, saat mencapai kemajuan baik di dalam pembuatan hardware maupun software. Banyak sekali pabrik yang dibangun di kota besar maupun kota kecil bahkan ada yang di tengah-tengah pemukiman warga. Limbah pabrik dapat menyebabkan lingkungan tercemar termasuk pencemaran pada air yang menimbulkan adanya penyakit. Alat pendeteksi ini dapat mendeteksi kadar logam pada air, sensor konduktivitas akan mendeteksi air dan dan menentukan layak atau tidaknya air tersebut berdasarkan Peraturan Menteri Kesehatan Republik Indonesia nomor 492 tahun 2010 tentang persyaratan kualitas air minum. Alat ini dapat mempermudah masyarakat untuk mengetahui dengan mudah layak atau tidaknya air pada lingkungan tersebut. Kata kunci — Alat Pendeteksi, Pendeteksi Logam pada Air