In this current digital era, people tend to shop online. Because of that, there are currently many e-commerce companies that can satisfy the various needs of society in shopping. Each company certainly has a strategy to attract consumers to shop at their shopping place. One of the media commonly used to attract consumers is social media. Tokopedia is one of the biggest marketplaces in Indonesia and is also active in utilizing Twitter as their social media mean. Therefore, it is essential for Tokopedia to pay attention to tweet contents interesting enough to be publicized. By applying text mining using K-Means Clustering algorithm, it can be seen which types of tweet contents that are attractive for Tokopedia consumers. Out of 885 Tokopedia tweets that have been collected, a clustering is then done using K-means algorithm, resulting 48 cluster tweets. Then, from the 48 clusters, they are further grouped into 5 major groups. Based on the results of the grouping, it can be seen that the most interesting content deals with quiz prizes and the least attractive content is on lifestyle.

Until now, the pandemic conditions of Covid-19 are still ravaging the world, even in Indonesia and West Java. Various attempts have been made to stop it. West Java implements Large Scale Social Restrictions, is known as Pembatasan Sosial Skala Besar (PSBB). However, over time, a discourse emerged to loosen PSBB. One of the World Health Organization’s (WHO) requirements to loosen is the effective reproduction rate of Corona Virus cases below 1. Therefore, this study focuses on predicting the number of cases in West Java. The methods based on multi-layer perception (MLP) and linear regression (LR). The data were obtained from the C Covid -19 positive case from March to mid-August 2020 in West Java. The experiments show that MLP reaches optimal if it used 13 hidden layers with learning rate and momentum = 0.1. The MLP had a smaller error than LR. Both of them predict the number of cases in the next 30 days from August 14, 2020. The results show that West Java will still have an increase in the number of new cases of Covid -19.

Satellite networks are recognized as the most essential communication infrastructures in the world today, which complement land networks and provide valuable services for their users. Extensive coverage and service stability of these networks have increased their popularity. Since eavesdropping and active intrusion in satellite communications are much easier than in terrestrial networks, securing satellite communications is vital. So far, several protocols have been proposed for authentication and key exchange of satellite communications, but none of them fully meet the security requirements. In this paper, we examine one of these protocols and identify its security vulnerabilities. Moreover, we propose a robust and secure authentication and session key agreement protocol using the elliptic curve cryptography (ECC). We show that the proposed protocol meets common security requirements and is resistant to known security attacks. Moreover, we prove that the proposed scheme satisfies the security features using the Automated Validation of Internet Security Protocols and Applications (AVISPA) formal verification tool and On-the fly Model-Checker (OFMC) and ATtack SEarcher (ATSE) model checkers. We have also proved the security of the session key exchange of our protocol using the Real or Random (RoR) model. Finally, the comparison of our scheme with similar methods shows its superiority.

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Kebun binatang merupakan tempat yang memiliki peran strategis terhadap aspek konservasi satwa, sosial ekonomi masyarakat, maupun lingkungan. Kebun Binatang Bandung sebagai salah satu kebun binatang di Indonesia sudah seharusnya dapat dikelola dengan baik dengan memberikan fasilitas pelayanan yang mumpuni. Namun pada saat ini Kebun Binatang Bandung masih belum memiliki fasilitas layanan petunjuk arah, peta, dan informasi satwa yang memadai. Hal tersebut melatarbelakangi adanya penelitian pengembangan aplikasi Sistem Informasi Geografis Kebun Binatang Bandung ini. Tujuannya agar pengunjung Kebun Binatang Bandung dapat lebih mudah dan nyaman dalam menjelajahi kebun binatang, serta bisa mendapatkan informasi lebih dalam mengenai satwa yang dilihatnya. Pengembangan aplikasi menggunakan metode pengembangan perangkat lunak Prototype yang dinilai baik untuk pengembangan aplikasi berskala kecil. Metode Prototype terdiri dari lima tahap pengembangan yakni Communication, Quick Plan, Modeling Quick Design, Construction of Prototype, dan Deployment Develivery Feedback. Sementara itu, aplikasi dibuat berbasis Progressive Web Application (PWA) yang mudah diakses namun tetap memberikan fitur-fitur yang menarik layaknya aplikasi native. Hasil pengembangan aplikasi kemudian diujicobakan dengan menggunakan metode System Usability Scale (SUS) dan Retrospective Think Aloud (RTA). Dari hasil pengujian, didapat didapat nilai usabilitas sebesar 81,43 (Skor SUS) yang tergolong ke dalam kategori Acceptable. Dengan demikian dapat disimpulkan bahwa aplikasi ini diterima dan layak untuk digunakan.