Judul: Keragaman Tumbuhan Invasif di PT Perkebunan  Nusantara II Deli Serdang, Sumatra Utara
Abstrak: Salah satu penghambat produktivitas perkebunan sawit adalah gulma. Beberapa gulma termasuk dalam kategori tumbuhan invasif. Penyebaran serta pertumbuhan dari tumbuhan invasif yang tidak terkendali dapat menyebabkan kerugian serta ancaman secara ekonomi maupun ekologi. Penelitian ini bertujuan menganalisis keragaman tumbuhan invasif di kawasan kebun kelapa sawit PT Perkebunan Nusantara II. Sampel tumbuhan diambil dengan membuat petak contoh pada 3 blok yang berbeda dan ditempatkan secara purposive sampling. Selanjutnya, dilakukan identifikasi spesies dan analisis data yang mencakup Indeks Nilai Penting (INP), indeks keanekaragaman, indeks kesamaan dan indeks kemerataan. Spesies tumbuhan invasif yang ditemukan sebanyak 20 dari 61 spesies gulma yang berasal dari 13 famili. Spesies invasif yang ditemukan memiliki habitus herba, semak dan perdu. Spesies invasif didominasi oleh tumbuhan dari famili Poaceae dan Asteraceae. Jenis Asystasia gangetica, Mitracarpus hirtus, Peperomia pellucida dan Phyllanthus urinaria ditemukan dalam tiga blok. Namun, berdasarkan nilai INP hanya tiga spesies yang dapat tergolong memiliki pengaruh pada komunitasnya yaitu Phyllanthus urinaria, Setaria plicata dan Peperomia pellucida., Several species of weeds which are categorized as invasive plants are one of the causes of inhibiting plantation productivity. The uncontrolled spread andgrowth of invasive plants can cause economic and ecological losses. This study aimed to analyze the diversity of invasive species in the palm oil plantation area of PT Perkebunan Nusantara II. Plant samples were taken by making sample plots in 3 different blocks and placed by purposive sampling. Furthermore, species identification and data analysis were carried out including the Important Value Index (IVI), diversity index, similarity index and evenness index. There are 20 invasive species from 61 weed species belonging to 13 families. The invasive species have a habitus of herbs, bushes and shrubs. Invasive species are dominated by species from the families Poaceae and Asteraceae. Asystasia gangetica, Mitracarpus hirtus, Peperomia pellucida and Phyllanthus urinaria species were found in all three blocks. However, based on the IVI value, only three species can be categoried affecting the community, namely Phyllanthus urinaria, Setaria plicata and Peperomia pellucida.
Keyword: diversity, IVI, invasive species, purposive sampling, weeds

Judul: Infestasi Gulma pada Agroekologi yang Berbeda di Perkebunan Kelapa Sawit (Elaeis guineensis Jacq.) Tambusai Estate, Kab. Rokan Hulu, Riau
Abstrak: Weed control in oil palm plantation can improve the productivity of oil palm trees. This in was carried out internship Tambusai Estate, Rokan Hulu, Riau, from February to May 2012. The objective of this apprentice was to improve the knowledge, skills, work experience and analyze factors that affect weed dynamic in different agroecological areal at oil palm plantation. Data were collected by direct method for primary data and indirect method for secondary data. Data of weed were collected using vegetation analysis of 1 m x 1m kuadran. The number of samples were 264. Weed were scored and tested using cluster analysis and shown as a dendogram. The results showed that agro-ecological factors, especially soil subgroup determined weed population and dominance in Tambusai Estate. Weed invasion on palm oil plantation spread based on the nature of the morphology, botany, and nature of damage to plants as well as palm oil is the difference in the form agroekologi subgroup of land. The humid soil conditions is an optimum for weeds Asystasia intrusa (Forssk.) Blume., Nephrolepsis bisserata (Sw.) Schott, and various kinds of other ferns which is the dominant weeds in Tambusai Estate.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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