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Dwi Lestari

Published : 43 Documents
Articles

## Title

### Found 2 Documents Search Journal : Jurnal Sains Dasar

The password agreement method based on matrix operation over Min-Plus algebra for safety of secret information sending Musthofa, Musthofa; Lestari, Dwi
Jurnal Sains Dasar Vol 3, No 1 (2014): Jurnal Sain Dasar
Publisher : Universitas Negeri Yogyakarta

#### Abstract

Key agreement protocol is a method in cryptography. Key agreement protocol is used to overcome the problem of sending secret information over communication lines. A secret key, called password, is needed to secure t he information. Both parties who exchange confidential information must agree on the same key. In this method, both parties exchange mutual general parameters that everyone can see, however from the general parameters the same passwords can be formed and not publicly known. One method that has been used is applying a series of matrix multiplication operation defined over a finite field. In this study, we constructed an algorithm in the form of a key agreement protocol that can be used in the password agreement method which the level of security based on algebraic problem of matrix operation over Z- min plus algebra. Min Plus algebra over Z, that is Z Ã { + Â¥ } with Z is the set of all integers equipped with the minimum and addition operation, Â is called idempotent semiring. The results showed that the application of matrix operation over min plus algebra can be used as key agreement protocol in securing secret information. Â  Key words: secret information, password, Min-Plus algebra
MATHEMATIC MODEL FOR SITY BUS SCHEDULING IN YOGYAKARTA Sahid, Sahid; Yuli S, Fitriana; Lestari, Dwi
Jurnal Sains Dasar Vol 4, No 2 (2015): Jurnal Sains Dasar
Publisher : Yogyakarta State University

#### Abstract

Various methods can be used to construct a mathematical model of the transportation problems. One model that can be used is a linear model. Several studies have used a linear model to get the schedule and the optimal route of bus trips. This research will build a mathematical model of a city bus transportation problems in DIY using linear models. Linear model is built to get the condition density city bus passengers on shifts respectively that morning, noon, and evening. After finding a suitable model, applied to the bus passengers data in Yogyakarta. From these results it can be seen the optimum conditions in terms of density, because the condition of the city bus at this time that quiet enthusiasts. Besides, the optimum density at each shift in the morning is 11 passengers, 10 passengers during the day, and evening 9 passengers.Â Keywords: transportation problems, the linear model, the optimal route, density