Judul: Periphyton Community Structure as a Bioindicator of Water Pollution in the Cibareno River, Sukabumi, West Java
Abstrak: Aktivitas antropogenik di sekitar Sungai Cibareno menyebabkan bertambahnya buangan limbah organik dan anorganik yang tersebar di sepanjang aliran sungai, sehingga kualitas perairan mengalami penurunan. Pemantauan kualitas air dapat dilakukan menggunakan indikator biologi seperti perifiton. Penelitian ini bertujuan untuk menganalisis kondisi perairan Sungai Cibareno berdasarkan struktur komunitas perifiton. Metode penentuan lokasi pengamatan yang digunakan adalah purposive sampling. Pengambilan contoh air dan perifiton dilakukan di enam stasiun dan setiap stasiun dilakukan tiga kali pengulangan. Identifikasi dan klasifikasi perifiton dilakukan berdasarkan genus. Parameter kualitas air yang dianalisis meliputi parameter fisika kimia. Analisis penentuan kualitas perairan menggunakan indeks saprobik. Hasil analisis menunjukkan struktur komunitas perifiton di perairan tersebut terdiri dari empat kelas. Jumlah jenis dan kelimpahan perifiton didominasi oleh Bacillariophyceae dari genus Navicula dan Nitzschia. Keanekaragaman perifiton di Sungai Cibareno tergolong sedang dan komunitas stabil. Model persamaan regresi linier yang didapatkan menunjukkan terdapat hubungan positif antara parameter kecerahan dan Dissolved Inorganic Nitrogen (DIN) terhadap kelimpahan total perifiton. Nilai saprobik berkisar 0,63­1,10 (β Meso/oligosaprobik) yang menunjukkan bahwa sungai telah tercemar ringan oleh bahan organik dan anorganik., Anthropogenic activities around the Cibareno River cause an increase in the discharge of organic and inorganic waste scattered along the river flow, so that the quality of the waters has decreased. Water quality monitoring can be carried out using biological indicators such as perifiton. This study aims to analyze the condition of the waters of the Cibareno River based on the structure of the perifiton community. The method of determining the observation location used is purposive sampling. Water and perifiton sampling was carried out at six stations and each station was carried out three repetitions. Identification and classification of periphytons is carried out by genus. The analyzed water quality parameters include chemical physics parameters. Analysis of water quality determination using saprobic index. The results of the analysis showed that the structure of periphyton communities in these waters consisted of four classes. The number of species and abundance of periphytons is dominated by Bacillariophyceae of the genera Navicula and Nitzschia. The periphyton diversity in the Cibareno River is moderate and the community is stable. The linear regression equation model obtained shows a positive relationship between the brightness parameter and Dissolved Inorganic Nitrogen (DIN) to the total abundance of perifiton. The saprobic value ranges from 0.631.10 (β Meso/oligosaprobic) which indicates that the river has been lightly polluted by organic and anorganic matter.
Keyword: saprobiotic index, biological indicator, periphyton, Cibareno River

Judul: Keterkaitan Struktur Komunitas Makrozoobenthos dengan Kualitas Air di Sungai Cibareno, Sukabumi, Jawa Barat
Abstrak: Aktivitas manusia termasuk pembuatan bendung di Sungai Cibareno, dapat mempengaruhi kualitas air sungai. Perubahan kualitas air sungai dapat berdampak pada struktur komunitas makrozoobenthos. Penelitian ini bertujuan untuk menganalisis hubungan struktur komunitas makrozoobenthos dengan kualitas air di Sungai Cibareno. Penelitian ini dilaksanakan di Sungai Cibareno, Sukabumi, Jawa Barat. Titik pengambilan sampel makrozoobenthos dan kualitas air terdiri dari enam stasiun, tiga stasiun sebelum dan tiga stasiun setelah rencana pembangunan bendung. Parameter kualitas air yang diambil meliputi oksigen terlarut (DO), suhu, pH, dan COD (diproporsikan ke dalam BOD). Analisis data meliputi indeks Morisita, indeks keanekaragaman, keseragaman, dan dominansi. Hubungan struktur komunitas makrozoobenthos dengan kualitas air dianalisis menggunakan PCA. Hasil analisis menunjukkan jenis makrozoobenthos yang banyak ditemukan yaitu ordo Ephemeroptera dari genus Epeorous sp. dan ordo Diptera dari genus Pentaneura sp. dan Diamesa sp. Indeks keanekaragaman tergolong sedang dan indeks dominansi setiap stasiun tergolong rendah. Pola persebaran jenis makrozoobenthos pada umumnya berkelompok. Analisis PCA menunjukkan bahwa kepadatan makrozoobenthos berkorelasi kuat dengan BOD yang berarti kepadatan makrozoobenthos dipengaruhi oleh bahan organik.
Keyword: Cibareno, macrozoobenthos, water quality

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