Tipe exponential smoothing yang dikaji pada penelitian ini adalah simple exponential smoothing, double exponential smoothing, double exponential smoothing dengan damped trend dan triple exponential smoothing. Tujuan dari penelitian ini adalah ingin mengetahui kinerja tipe exponential smoothing yang paling baik dalam meramalkan nilai tengah tukar harian rupiah terhadap USD. Kinerja metode peramalan tipe exponential smoothing sangat bergantung pada pemilihan nilai parameter pemulusan yang terkandung pada persamaan matematikanya. Oleh karena itu, nilai parameter terbaik untuk setiap tipe exponential smoothing akan dicari menggunakan program solver. Mendapatkan nilai parameter terbaik merupakan permasalahan optimasi. Pada penelitian ini, masalah optimasi nilai parameter ini adalah meminimalkan kesalahan peramalan berdasarkan MAPE dengan fungsi kendalanya adalah persamaan peramalan untuk setiap tipe exponential smoothing. Tahapan penelitian dibagi menjadi 2 segmen yaitu tahap pelatihan dan tahap pengujian. Tahap pelatihan menghasilkan nilai parameter pemulusan terbaik. Nilai parameter terbaik kemudian dijadikan sebagai input untuk tahap pengujian. Tahap pengujian ini untuk mengetahui kinerja masing-masing tipe exponential smoothing. Kinerja tipe exponential smoothing diukur berdasarkan besarnya kesalahan peramalan menggunakan MAPE, MAD dan RMSE. Hasil pengujian menunjukkan bahwa kinerja metode double exponential smoothing dengan damped trend paling baik dibandingkan tipe exponential yang lain dengan MAPE = 0.840, MAD = 117.28 dan RMSE = 186.07.

The technology that is currently developing is the use of QR-Code. QR-Code can convey information quickly with the acquisition of fast responses as well. QR-Code can be used on smartphones. Some media and companies widely use the QR-Code in Indonesia. QR-Code is not only used as an application identity but is also used as a means of effective, simple and modern business promotion. Making information systems for Sentra Ikan Bulak Surabaya is done by using QR-Code technology as a means of product promotion in the sales process. Research that has been done can run well and can support and be useful in improving the means of promotion. Traders find it easier to collect data on existing systems. Buyers can access the site and see reviews from other buyers so buyers will feel interested in buying the product.

Penggunaan citra dalam kehidupan sehari-hari mengalami peningkatan seiring berkembangnya teknologi informasi. Untuk itu diperlukan sebuah cara agar data citra dapat ditransmisikan dengan aman. Salah satunya adalah dengan melakukan enkripsi pada citra. Citra terenkripsi akan membuat citra hanya dapat dibaca oleh pihak yang berwenang saja. Skema yang digunakan pada proses enkripsi dapat berupa permutasi. Pada penelitian ini menggunakan Arnold cat map untuk melakukan permutasi pada enkripsi citra. Namun permutasi saja tidak cukup aman untuk mengenkripsi citra. Citra yang telah dipermutasi selanjutnya ditambah dengan algoritma lain berbasis chaos. Beta chaotic map digunakan dalam penelitian ini karena memiliki parameter yang lebih banyak dibandingkan dengan map jenis lain. Dengan parameter yang lebih besar maka akan memperkuat hasil enkripsi. Hasil pengujian yang dilakukan pada penelitian ini menunjukkan bahwa skema enkripsi memiliki ketahanan terhadap serangan brute force dan serangan analisis histogram. Citra asli akan memiliki bentuk yang sangat berbeda dengan citra hasil enkripsi yang dibuktikan dengan perhitungan nilai NPCR.

The rapid progression of exchange data by public networks is important, especially in information security. We need to keep our information safe from attackers or intruders. Furthermore, information security becomes needed for us. Many kind cipher methods of cryptography are improved to secure information such as monoalphabetic cipher and polyalphabetic cipher. Cryptography makes readable messages becoming non-readable messages. One of the popular algorithms of a polyalphabetic cipher is Vigenere cipher. Vigenere cipher has been used for a long time, but this algorithm has weaknesses. The calculation of the encryption process is only involving additive cipher, it makes this algorithm vulnerability to attacker based on frequency analysis of the letter. The proposed method of this research is making Vigenere cipher more complex by combining monoalphabetic cipher and Vigenere cipher. One of the monoalphabetic ciphers is Affine cipher. Affine cipher has two steps in the encryption process that are an additive cipher and a multiplicative cipher. Our proposed method has been simulated with Matlab. We also tested the vulnerability of the result of encryption by Vigenere Analyzer and Analysis Monoalphabetic Substitution. It shows that our method overcomes the weakness of Vigenere Cipher. Vigenere cipher and Affine cipher are classical cryptography that has a simple algorithm of cryptography. By combining Vigenere cipher and Affine cipher will make a new method that more complex algorithm.

Retinal blood vessels are a very important object to diagnosing illness. Fast, automatic, adaptive, and accurate systems to segment the retinal vessels are particularly useful. The retinal blood vessels can be detected by edge detection. This research will compare the edge detection techniques with adaptive ant colony optimization (Adaptive ACO). Generally, the early ants on the conventional ant colony optimization (ACO) are randomly distributed. This condition can cause the ant distribution imbalances. Based on this problem, the ant distribution modification on ACO is proposed to optimize the ant placement based on the gradient. The gradient values are used to determine the ants’ placement. The ants are not randomly distributed but placed in the highest gradient. The so-called Adaptive ACO is expected to be used for better and faster path discovery optimization. The average PSNR of Prewitt edges, Sobel edges, conventional ACO, and the proposed method are 11.605, 11.913, 9.783, and 15.874 respectively. The PSNR of the proposed method has the greatest value than others. It shows that the placement of ants based on gradient can improve edge detection accuracy. The application of the Adaptive ACO method has successfully optimized the result of retinal vessel edge detection.