Judul: Uji Orientasi Arah Penempatan Sensor Tube Solarimeter terhadap Pengukuran Koefisien Transmisi pada Pertanaman Jagung Manis
Abstrak: Radiasi yang terbaca di bawah tajuk merupakan fungsi sudut datang matahari dan karakter tajuk tanaman. Arah penempatan alat ukur yang tidak tepat berpotensi membiaskan hasil pengukuran. Orientasi alat ukur radiasi transmisi yang berbeda di bawah tajuk tanaman jagung manis (Zea mays saccharata Sturt.) perlu diuji coba. Penelitian ini bertujuan untuk mengevaluasi penempatan solarimeter yang tepat, menerangkan karakter transmisi radiasi di bawah tajuk dan koefisien pemadaman tajuk tanaman jagung manis dalam berbagai perlakuan arah baris dan jarak tanam. Penelitian dilakukan pada bulan Maret hingga Juni 2013 berlokasi di Dramaga, Bogor, Jawa Barat pada ketinggian 240 meter diatas permukaan laut. Hasil penelitian menunjukkan bahwa respon sensor semakin seragam dengan bertambahnya indeks luas daun. Sensor yang ditempatan dengan posisi diagonal mampu menghasilkan nilai transmitansi yang konsisten terhadap arah sudut datang matahari berbeda pada semua perlakuan. Radiasi yang ditransmisikan tanaman jagung manis menurun dengan peningkatan indeks luas daun dan konstan pada nilai 0.6 setelah indeks luas daun (ILD) melebihi 1. Nilai koefisien pemadaman tajuk (k) berbanding terbalik dengan nilai indeks luas daun dan konstan pada rataan nilai 0.3 setelah ILD mencapai 1. Nilai k perlakuan Utara Selatan rapat 13% lebih besar dari perlakuan lainnya yang mengindikasikan intersepsi radiasi lebih optimal.
Keyword: orientasi sensor tube solarimeter, transmisi radiasi, koefisien pemadaman tajuk, jagung manis.

Judul: Karakteristik Intersepsi Radiasi Matahari dan Produksi Tanaman Jagung Manis pada Arah Baris dan Kerapatan Berbeda
Abstrak: This study was conducted to determine the effect of row planting direction and plant population density on the change of specific leaf area (SLA), leaf area index (LAI), radiation use efficiency (RUE) and growth of sweet corn. The research was conducted from March to June 2013 in Cikabayan Research Station IPB Darmaga-Bogor, West Java, at altitude of ± 240 masl. The row planting direction was TB (East-West direction) and US (North-South direction). The planting spacing was J20 (70 x 20 cm) and J40 (70 x 40 cm). The meteorology factors being observed were the intensity of radiation, air temperature and humidity. Agronomic variables factors being observed were plant height, number of leaves, dry weight and yield component. The results showed the combination treatment of row direction and planting spacing did not significantly affect plant height, leaf number and total dry weight. However, the treatment has significant affect on dry plant at harvest. The interception of solar radiation in US treatment was 11% higher than the TB, while J20 treatment has 3% higher than J40. Radiation use eficiency of treatment TBJ20, TBJ40, USJ20, USJ40 were 2.97, 2.75, 3.16, and 3.14 g MJ-1 respectively. Dry seed yield of J20 was 5.98 ton ha-1, which was 20% greater than J40 population. Harvest index for TBJ20, TBJ40, USJ20 and USJ40 are 0.23, 0.19, 0.25 and 0.20.
Keyword: planting density, row direction, harvesting product, biomass production, radiation use efficiency, sweet corn

Judul: The Exploration of Discrete Logarithm over Finite Field GF(3m)
Abstrak: The security of many public~key algorithms is based on the problem of finding discrete logarithms. The generalized discrete logarithm problem is the following: given a finite cyclic group G of order n, a generator a of G, and an element fl E G, find the integer x, 0 ~ x ~ n - 1, such that 0: = fl. Algorithm for discrete logarithm problem focused on Menezes et al. (1997) that consist of exhaustive search algorithm, the baby-step giant-step algorithm, Pollard's rho algorithm, Pohlig-Hellman algorithm, and index-calculus algorithm. These algorithms are explorated to be used in discrete logarithm problem over finite field GF(3m ). The exploration also produces some algorithms, i.e. naif negative algorithm, baby-step mother-step algorithm, baby-step mother free-step algorithm, and baby-step free-step algorithm. All algorithms implemented using Maple 11. The Pohlig-Hellman and baby-step giant-step algorithms are efficient enough to be used in discrete logarithm problem over finite field GF(3m ) for m < 20.
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