Judul: Efektivitas Akun Twitter @EHIndonesia sebagai Media untuk Gerakan Earth Hour Indonesia 2012
Abstrak: Earth Hour is a social movement which turn off the light and others electronic devices for one hour. Earth Hour held every fourth week in March. Earth Hour followed by many countries in the world, including Indonesia. Earth Hour use some media to campaign this movement to people, one of the media is Twitter with account Twitter @EHIndonesia. The objective of this research is to analyze relation between intensity of Twitter access and Twitter effectiveness as a media of social movements with cognitive, affective, and behavioral factors. The methods of the research are quantitative and supported with qualitative data. This research results show that: 1) there is significant correlation between ease of access to the internet and intensity of access to internet; 2) there is significant correlation between intensity of access to internet and behavioral factor; and 3) Twitter effective as media of social movements.
Keyword: 

Judul: Efektivitas Instagram “Earth Hour Bogor” sebagai Media Kampanye Lingkungan.
Abstrak: Media sosial merupakan media baru yang memiliki karakteristik komunikasi yang lebih interaktif dibandingkan media konvensional. Earth Hour Bogor adalah gerakan sosial yang memanfaatkan media sosial instagram sebagai media kampanye mereka. Tujuan penelitian adalah analisis efektivitas instagram @ehbogor sebagai media kampanye dan faktor-faktor yang mempengaruhinya. Penelitian ini menggunakan metode kuantitatif menggunakan kuesioner dengan didukung data-data kualitatif. Hasil penelitian menunjukkan media sosial Instagram @ehbogor efektif dalam menstimulasi perhatian followers, menimbulkan ketertarikan untuk mengetahui lebih lanjut, keinginan untuk berpartisipasi, serta mengikuti kegiatan kampanye yang diselenggarakan dan mengajak orang lain. Faktor-faktor yang mempengaruhi hal tersebut adalah lokasi tempat tinggal dan frekuensi informasi kampanye yang disampaikan pada tahap perhatian (attention). Pada tahap ketertarikan (interest) yaitu jenis pekerjaan, frekuensi responden dalam mengakses instagram dan kejelasan informasi kampanye. Pada tahap keinginan (desire) tidak ditemukan variabel yang mempengaruhi, sedangkan pada tahap tindakan (action) yaitu lokasi tempat tinggal dan motivasi responden dalam mengakses Instagram.
Keyword: Earth Hour Bogor, instagram, kampanye lingkungan, media sosial

Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm