Judul: Uji Mikrobiologi dan Kandungan Unsur Kimia Masker Wajah Berbahan dasar Ekstrak Pisang dan Madu.
Abstrak: Masker wajah berbahan dasar alami menjadi pilihan saat ini. Namun, belum ada penelitian terhadap mikroba dan unsur kimia serta logam berat dari masker tersebut. Penelitian bertujuan mengidentifikasi keberadaan mikroba serta logam berat di dalam masker wajah ekstrak pisang dan madu. Metode meliputi uji angka lempeng total (ALT/TPC), uji coliform, pewarnaan Gram, kurva pertumbuhan bakteri TPC, uji angka kapang khamir (AKK), kurva pertumbuhan khamir, dan pengujian keberadaan logam berat menggunakan Micro-XRF Spectrometer. Uji TPC menghasilkan 6.1 x 104 koloni/g, hasil uji coliform menunjukkan adanya bakteri gram positif bukan Escherichia coli. Rentang hidup bakteri hanya 9 jam pada semua uji mengarah pada dugaan bakteri asam laktat (BAL). Uji AKK dan kurva pertumbuhan menunjukkan terdapat 46 x 103 koloni/g dengan rentang hidup 76 jam. Masker teruji negatif logam berat. Hasil uji TPC dan AKK melampaui batas maksimum BPOM, yaitu 103 koloni/g.
Keyword: angka lempeng total, angka kapang khamir, coliform, masker wajah, Micro-XRF spectrometer

Judul: Aktivitas antibakteri Spirulina platensis terhadap bakteri penyebab jerawat dan karakteristik masker berbasis Spirulina dan kolagen.
Abstrak: Penelitian ini menggunakan Spirulina yang dikultur dalam media media organik (pupuk Urea, Plant Catalyst dan RI1) dan kolagen dari kulit ikan kakap merah. Tujuan penelitian menentukan karakteristik Spirulina, karakteristik kolagen serta karakteristik fisik, kimiawi dan mikrobiologis sediaan masker. Tahapan penelitian meliputi kultivasi dan pemanenan S. platensis, ekstraksi biomasa menggunakan etanol, ekstraksi kolagen menggunakan pelarut NaOH dan asam asetat serta formulasi masker. Analisis meliputi fitokimia, rendemen, aktivitas antibakteri, analisis sensori, homogenitas, viskositas, daya sebar dan total mikroba. Ekstrak S.platensis mampu menghambat bakteri penyebab jerawat Staphylococcus aureus, Stapylococcus epidermidis serta Propionibacterium acne dengan diameter zona hambat terbesar pada ekstrak 100 μg/sumur. Kolagen ikan kakap berwarna putih, dengan rendemen sebesar 6.4±0.28%, dan pH 6.46±0.15. Sediaan masker yang dihasilkan memiliki nilai sensori berkisar 3.57- 4.23 dalam kategori suka, homogen, daya sebar 6.6±0.28, viskositas 2500±70.71, pH 6.29±0.06, dan total mikroba <1x10 cfu/g. Sediaan masker mampu menghambat bakteri penyebab jerawat S. aureus, S. epidermidis serta P. acne.
Keyword: antibakteri, kolagen, masker, Spirulina platensis

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