Judul: Pengolahan Limbah Cair Rumah Potong Hewan (RPH) dengan Metode Fotokatalitik TiO2: Pengaruh Waktu Kontak terhadap Kualitas BOD5, COD dan pH Efluen
Abstrak: Limbah cair Rumah Potong Hewan diolah melalui proses fisik, biologis dan kimia. Salah satu cara pengolahan limbah cair melalui proses kimia dalah dengan cara fotokatalitik yaitu pengolahan dengan cara penambahan katalis dan cahaya pada limbah tersebut. Dengan proses fotokatalitik limbah organik akan terdegradasi menjadi CO2 dan H2O sehingga diharapkan dapat mereduksi kandungan Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) , pH dan daya hantar listrik yang merupakan tolok ukur pencemaran oleh zat-zat organik.
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Judul: Pengolahan Limbah Cair Batik Pewarna Alami dengan Teknik Elektrokoagulasi
Abstrak: Limbah cair batik pewarna alami mengandung polutan seperti bahan organik, padatan tersuspensi, dan minyak dan lemak yang berpotensi mencemari perairan dan memiliki dampak buruk terhadap manusia maupun makhluk hidup lainnya. Oleh karena itu, perlu dilakukan pengolahan terlebih dahulu sebelum dibuang ke perairan. Pengolahan limbah dapat dilakukan dengan teknik elektrokogulasi menggunakan elektroda aluminium karena dinilai efektif dalam pengolahannya. Penelitian ini bertujuan mendapatkan kombinasi terbaik dari tegangan 15, 18, 21, dan 24 V dan waktu kontak 15, 30, 45, dan 60 menit dalam menurunkan polutan. Karakteristik limbah ini antara lain pH sebesar 5.95, warna sebesar 20 900 PtCo, kekeruhan sebesar 193 NTU, Total Suspended Solid (TSS) sebesar 672 mg/L, amonia sebesar 4.35 mg/L, Chemical Oxygen Demand (COD) sebesar 11 484 mg/L, dan minyak dan lemak sebesar 4.79 mg/L. Hasil uji lanjut Duncan menyatakan kombinasi besar tegangan 24 V dan waktu kontak 60 menit memberikan pengaruh yang berbeda nyata terhadap perubahan nilai pada semua parameter. Efisiensi penurunan polutan pada kondisi tersebut yaitu 39.47% warna, 69.43% kekeruhan, 62.28% TSS, 63.91% amonia, 94.48% COD, dan 94.78% minyak dan lemak. Pada kondisi besar tegangan 24 V dan waktu kontak 60 menit, biaya pengolahan sebesar Rp 134.76/L.
Keyword: limbah cair batik pewarna alami, elektrokoagulasi, tegangan, waktu kontak

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