Judul: Kajian mutu fisokimia dan mikrobiologi air minum perumahan PT Badak Natural Gas Liquefaction
Abstrak: PT Badak merupakan salah satu perusahaan penghasil LNG (Liquefied Natural Gas) terbaik di dunia. Selain menghasilkan LNG, salah satu kegiatan PT Badak adalah mengelola air sumur tanah menjadi air minum untuk memenuhi kebutuhan masyarakat komplek Badak. Unit pengolahan air minum perumahan terletak pada WTP(Water Treatment Palnt) 48 dan 49. Masalah yang terdapat pada hasil air olahan WTP 48 dan 49 adalah sering terindikasi yang berwarna merah kecoklatan dan berbau klorin. Kondisi ini menunjukkan bahwa air tersebut mempunyai masalah dan penyimpangan terhadap standar mutu air minum. Oleh karena itu, air minum perusahaan PT Badak perlu dikaji ulang dan ditindak lanjuti agar meminimalkan bahaya bagi peminumnya.
Keyword: 

Judul: Population Perceptions of The Microbiological Quality of Bottled Drinking Water: Study Case in Bogor
Abstrak: Air minum merupakan sumber kehidupan yang telah merambah menjadi produk komersial seperti air minum dalam kemasan (AMDK). Koliform dan Escherichia coli menjadi indikator higienitas air minum. Analisis oleh laboratorium yang mengaplikasikan ISO 17025:2017 harus melakukan verifikasi terhadap metode pengujian yang akan diterapkannya. Penelitian ini terbagi menjadi dua bagian, yaitu uji verifikasi dan survei. Uji verifikasi metode analisis bakteri koliform dan E. coli pada AMDK sesuai dengan SNI 3554:2015 dengan metode filtrasi yang bertujuan untuk memperoleh metode terverifikasi. Karakteristik kinerja yang dilakukan meliputi parameter akurasi (perolehan kembali) dan presisi (RSD). Hasil menunjukkan nilai derajat keterulangan kembali dari metode ini sebesar 65,00% dan 95,38% (inokulum 101) dan 19,44% dan 45,13% (inokulum 102). Nilai RSD sebesar 24,40% dan 7,23% (inokulum 101) dan 15,49% dan 31,59% (inokulum 102). Proses verifikasi pada inokulum 100 dan 101 berhasil dilakukan. Nilai akurasi dan presisi terlalu kecil pada inokulum 102 sehingga verifikasi metode pengujian bakteri koliform dan E. coli pada AMDK belum berhasil. Survei persepsi mikrobiologis air minum bertujuan untuk mengetahui persepsi penduduk terhadap kualitas mikrobiologis air minum. Responden sebanyak 233 orang dari mahasiswa dan ibu rumah tangga. Hasilnya menunjukkan atribut yang paling penting adalah kebersihan air minum. Faktor umur, pendidikan dan pekerjaan memiliki hubungan yang signifikan persepsi konsumen dan pemilihan jenis air minum. Persepsi tentang keamanan setiap jenis air minum berpengaruh pada perlakuan sebelum meminum air., Drinking water is a source of life that has penetrated into commercial products such as bottled drinking water (AMDK). Coliforms and Escherichia coli are the indicators of water hygiene. Laboratories that comply ISO 17025:2017 must verify its analysis method. This research is divided into two parts, verification nd survey. The verification test for analysis method for coliform and E. coli on AMDK in accordance with SNI 3554: 2015 with filtration method that aims to obtain a verified method. The performance characteristics are parameters of accuracy (recovery) and precision (RSD). The results showed that the recovery of this method are 65.00% and 95.38% (inoculum 101) and 19.44% and 45.13% (inoculum 102). The RSD values ere 24.40% and 7.23% (inoculum 101) and 15.49% and 31.59% (inoculum 102). Verification process at inoculum 100 and 101 has been successfully carried out. The accuracy and precision values are too small at inoculum 102 so that the verification of the testing methods for coliform bacteria and E. coli on bottled water has not been successful. Some accuracy and precision that are too small so the verification of the testing method for coliform and E. coli on AMDK has not been successful. The microbiological perception survey of drinking water aims to determine the perception of population on the microbiological quality of AMDK. There were 233 respondents from students and housewives. The results show that the most important attribute is clean drinking water. The factors of age, education and occupation have a significant relationship with consumer perceptions and the choice of drinking water. Perceptions of each type drinking water safety have effect on the treatment before drinking water.
Keyword: Air minum dalam kemasan, Escherichia coli, koliform, persepsi, verifikasi

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