Judul: Soil Erosion Study in The Gap Planting Research Area  with Jabon Putih in The PT. Sarmiento Parakantja Timber
Abstrak: Peningkatan produktivitas hutan alam dapat dilakukan dengan menerapkan teknik tanam rumpang. Tujuan dari teknik tanam rumpang adalah untuk merehabilitasi hutan alam terdegradasi dengan penanaman fast growing species lokal non Dipterocarpaceae yang berdaur pendek (5-8 tahun) di dalam areal rumpang. Penelitian ini bertujuan untuk mendapatkan informasi erosi tanah yang terjadi akibat tanam rumpang pada kondisi areal hutan alam, simpukan dan jalur tanam. Penelitian dilakukan pada bulan Mei 2021. Penelitian dilakukan pada dua kelas kelerengan yaitu kelas datar-landai dan kelas sedang. Hasil uji statistik menunjukkan tidak berbeda nyata antara besarnya erosi tanah pada kelas lereng datar-landai dan kelas lereng sedang. Hasil penelitian menunjukan besar erosi tanah yang terjadi secara berturut-turut dari yang terbesar ke terkecil adalah di areal hutan alam, di areal jalur tanam dan di areal jalur simpukan., Increasing the productivity of natural forests can be done by applying the gap planting technique. The purpose of the gap planting technique is to rehabilitate degraded natural forests by planting local intolerant fast-growing species with short cycles (5-8 years) in the gap area. This study aims to obtain information on soil erosion that occurs due to gap planting activities on the condition of natural forest areas, erosion barrier strips, and planting strips. The study was conducted in May 2021. The study was conducted on two slope classes, the flat to sloping class and the moderate class. The result of statistical tests showed that the magnitude of erosion on the flat to sloping class and moderate class was not significantly. The results showed that the amount of soil erosion that occurred successively from the largest to the smallest was the area of natural forest, planting area, and erosion barrier area.
Keyword: erosi tanah, hutan alam terdegradasi, rehabilitasi, tanam rumpang, degraded natural forests, gap planting, rehabilitation, soil erosion

Judul: The Effect of Slopes on Soil Erosion in the Gap Planting Research Area of PT Sarmiento Parakantja Timber
Abstrak: Tanam Rumpang Tebang Rumpang (TRTR) merupakan sistem silvikultur yang diharapkan menjadi solusi peningkatan produktivitas hutan alam terdegradasi menggunakan teknologi tanam rumpang. Areal rumpang dimanfaatkan dengan menanam jenis pohon komersial setempat yang cepat pertumbuhannya dan berdaur pendek (5-8 tahun). Penelitian ini bertujuan untuk mengetahui pengaruh lereng terhadap erosi tanah yang terjadi akibat tanam rumpang. Penelitian dilakukan pada dua kelas lereng yakni kelas datar-landai dan kelas sedang. Hasil penelitian menunjukkan erosi tanah yang terjadi tertinggi pada areal simpukan, diikuti oleh erosi tanah di areal jalur tanam, dan yang terendah di areal hutan alam. Uji statistik menunjukkan bahwa erosi yang terjadi pada kondisi areal hutan alam, jalur simpukan dan jalur tanam tidak berbeda nyata. Pengaruh kelas lereng datar-landai dan kelas lereng sedang terhadap besarnya erosi di areal rumpang tidak berbeda nyata. Demikian pula besarnya erosi yang terjadi di areal rumpang dan di areal hutan alam terdegradasi juga tidak berbeda nyata., The gap planting and gap clear cutting (TRTR) silviculture system is projected to boost the productivity of damaged natural forests utilizing gap planting technology. The gap area is used by planting a local commercial fast-growing tree species with short-rotation (5-8 years). The goal of this study is to know how slopes affect soil erosion caused by gap planting. The study was conducted in two slope classes, namely the flat to sloping class and the medium class. The results showed that soil erosion occurred the highest in barrier areas, followed by soil erosion in planting path areas, and the lowest in natural forest areas. According to statistical analysis, there were no significant differences in the erosion that took place on planting path areas, barrier paths, and natural forest areas. The amount of erosion in the gap area is not considerably different depending on whether the slope is flat to sloping or medium. Similarly, the amount of erosion that occurs in the gap areas and in the degraded natural forest area is also not significantly different.
Keyword: Degraded natural forest, Gap planting, Soil erosion, Slopes

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.
Keyword: