Judul: Identifikasi dan deskripsi penyakit pada tegakan Ceiba pentandra Gaertn di areal HTI transmigrasi PT.Nusa Wana Raya, Propinsi Dati I Riau
Abstrak: Kapuk randu (Ceiba pentandra Gaertn) merupakan salah satu jenis tanaman yang dipilih oleh PT. Nusa Wana Raya untuk tanaman HTI-nya. Sebagaimana HTI jenis lain, HTI kapuk randu diperkirakan akan menghadapi masalah munculnya penyakit yang sewaktu-waktu siap menyerang, baik yang nyata dapat dilihat akibatnya dengan segera maupun yang tidak nyata tampak, tetapi secara ekonomis dapat merugikan dalam jangka panjang. Untuk mengendalikan serangan penyakit, baik pencegahan maupun pemberantasan, salah satu informasi yang diperlukan adalah mengenai penyebab penyakit. Oleh karena itu penelitian mengenai identifikasi dan deskripsi penyakit pada tegakan Ceiba pentandra merupakan upaya yang bermanfaat. Tujuan penelitian ini adalah mengetahui berbagai jenis fungi penyebab penyakit pada tegakan randu, bagian pohon yang diserang dan derajat kerusakan di areal ΗΤΙ Transmigrasi PT. Nusa Wana Raya, Propinsi Dati I Riau. Penelitian dilakukan di areal HTI Transmigrasi PT. Nusa Wana Raya Propinsi Dati I Riau, Laboratorium Perlindungan Hutan Fakultas Kehutanan IPB dan Laboratorium Mikrobiologi Kebun Raya Bogor sejak bulan Agustus sampai November 1996. Untuk pengambilan data di lapangan digunakan teknik penarikan contoh systematic sampling with random start, dengan intensitas sampling 0,5%. Pengamatan dilakukan terhadap gejala dan tanda penyakit, bagian pohon yang terserang, derajat kerusakan dan jumlah pohon yang terserang pada petak ukur berupa lingkaran seluas 0,1 ha (jari-jari 17,8 m). Data tersebut ditunjang dengan data kondisi lingkungan di areal HTI. Untuk penilaian derajat kerusakan digunakan kriteria penilaian dari Hadi and Nuhamara (1995) yang dimodifikasi. Sedangkan identifikasi fungi dilakukan dengan cara mengisolasi fungi, yaitu menanam material tanaman sakit pada PDA dalam cawan petri. Setelah fungi tumbuh dilakukan pemurnian, kemudian dibuat preparat dan dilakukan pengamatan di bawah mikroskop untuk mendapatkan ciri-ciri mikroskopis jamur. Berdasarkan ciri-ciri...
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Judul: Identification and Pathogenicity Test of the Causes of Leaf Blight Disease in Teak at PT. Solusi Bangun Indonesia Nursery
Abstrak: Jati (Tectona grandis Linn) merupakan tanaman dari famili Verbenaceae yang digunakan sebagai tanaman revegetasi karena adaptif pada lahan kritis, tahan terhadap penyakit dan bernilai ekonomi tinggi. Permasalahan penyakit jati banyak terjadi di persemaian. Penelitian ini bertujuan untuk mengidentifikasi patogen penyebab penyakit hawar daun di Persemaian PT. SBI. Metode penelitian dilakukan dengan sensus di lapangan dan uji postulat Koch. Ditemukan hawar daun dengan luas serangan sebesar 93%, dengan ciri nekrosis. Empat isolat yang diberi kode S1, S2, S3, dan S4 didapatkan dengan uji postulat Koch. Hasil identifikasi cendawan menunjukkan bahwa isolat S1 dan S2 adalah Rhizoctonia sp. dengan ciri karakteristik hifa bersekat, sudut percabangan 90°, miselia sterilia dan memiliki struktur moniloid. Isolat S3 dan S4 adalah Curvularia sp. dengan ciri keberadaan hifa yang bersepta dan konidia yang terdiri atas 4-5 sel membentuk rantai., Teak (Tectona grandis Linn) is a plant from the Verbenaceae family used for revegetation due to its adaptability to critical lands, disease resistance, and high economic value. Problems with teak diseases frequently occur in nurseries. This study aims to identify the pathogens causing leaf blight disease in the nurseries of PT. SBI. The research methods included field surveys and Koch's postulates tests. Leaf blight with an attack rate of 93% was found, characterized by necrosis. Four isolates, coded S1, S2, S3, and S4, were obtained through Koch's postulates tests. Fungal identification results showed that isolates S1 and S2 were Rhizoctonia sp., characterized by septate hyphae, 90° branching angles, sterile mycelia, and monilioid structures. Isolates S3 and S4 were Curvularia sp., characterized by septate hyphae and conidia consisting of 4-5 cells forming chains.
Keyword: Agaricomycetes, Dothideomycetes, postulat Koch, patogenesitas, nekrosis

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