Judul: Sifat-sifat Tanah pada Lahan Gambut Satu Juta Hektar di Kalimantan Tengah dan Potensinya untuk Pertumbuhan Tanaman Jagung (Zea mays)
Abstrak: Tanah gambut dalam Taksonomi Tanah didefinisikan antara lain sebagai tanah yang mengandung C-organik lebih dari 12% (bahan organik lebih dari 20%) bila tanah tidak mengandung liat, atau C-organik lebih dari 18% (bahan organik lebih dari 30%) bila tanah mengandung liat 60% atau lebih dan tebalnya lebih dari 40 cm. Bila kandungan liat antara 0-60%, maka kandungan C-organik harus sebesar (12 + (% liat x 0,1))% (Soil Survey Staff; 1998). Sifat dan potensi tanah gambut berbeda-beda, dari sangat kurus sampai subur, tergantung dari faktor-faktor yang mempengaruhi pembentukannya seperti kualitas air yang menggenangi rawa-rawa tempat terbentuknya tanah gambut tersebut, substrat tanah mineral di bawah tanah gambut dan jenis vegetasi yang menjadi tanah gambut.
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Judul: Karakteristik dan genesis gambut pedalaman pada substratum pasir dan liat di Kalimantan Tengah serta potensinya untuk pertanian
Abstrak: Gambut pedalaman belum banyak dimanfaatkan, hal ini karena umumnya mempunyai tingkat kesuburan alami rendah. Rendahnya tingkat kesuburan ini berhubungan dengan tanah mineral yang menjadi substratum gambut tersebut berupa pasir kuarsa dan liat yang miskin unsur hara. Miskinnya unsur hara disebabkan oleh tidak adanya pengaruh luapan pasang air laut dan kurangnya pengkayaan dari daerah hulu sungai. Dalam penelitian ini dipelajari karakteristik, genesis, dan potensi gambut untuk pertanian. Untuk tujuan tersebut dilakukan penelitian pada lokasi bekas wilayah Proyek Pengembangan Lahan Gambut 1 juta hektar Kalimantan Tengah yang mewakili gambut pedalaman bersubstratum pasir (Daerah Kerja C) dan substratum liat (Daerah Kerja B).
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Judul: Analisis performance algoritme paralel block cipher RC6 menggunakan message passing interface (MPI)
Abstrak: RC6 algorithm is a block cipher algorithm, which is one of the finalists in the AES competition. One of the RC6 algorithm parameters is the size of the block, where a larger block size is used the more time required to perform encryption-decryption. In this research the RC6 algorithm would be parallelized by dividing the data to each processor and the performance of the RC6 algorithm would be analyzed. Parallel implementation of the RC6 algorithm uses Message Passing Interface (MPI). The purpose of this research is to measure and analyze the performance of parallel RC6 algorithm. This research uses 4 computer with Linux operating system. This research uses files ASCII text and binary for the experiment. Each file will do the experiment three times repetition to take the average value. The results of this research show that execution time of parallel RC6 algorithm at the process of encryption and decryption is longer than execution time of sequential RC6 algorithm. For example, for file size of 249,149,712 bytes, encryption execution time of sequential RC6 algorithm is 17.91 seconds, whereas using the number of processors as many as 2, 4, 6 and 8, respectively are as follows 18.34 seconds, 20.37 seconds, 17.51 seconds and 18.93 seconds. The results of encryption execution time show that the encryption execution time by using the processor number of 4 is the slowest one. The speedup of parallel RC6 algorithm is less than one or smaller than the speedup of sequential RC6 algorithm. The speedup of parallel RC6 algorithm also not ideal because ideally speedup is equal to the number of processors used. The efficiency of parallel RC6 algorithm becomes lower along with more processor used. The resulting efficiency is far away from the optimum efficiency value, that is one, and it is not constant. To maintain the efficiency values if the number of processors is increased from p to p ' the input size should be increased in fraction of p'2 / p2. The cost of parallel RC6 algorithm increases as more processors are used. The resulting cost greater than the optimal cost value that is equal to Ts. The resulting overhead values become greater when the number of processors are increased. The results of this research indicate that the RC6 algorithm is not good when it is parallelized with domain decomposition method and using MPI. This is because the RC6 algorithm has a fast computational process, but it has the long communication time, so the total execution time of parallel RC6 algorithm longer than sequential RC6 algorithm.
Keyword: block cipher, RC6 algorithm, parallel, Message Passing Interface (MPI), Linux, Performance metric, execution time, speedup, efficiency, isoefficiency