Judul: Perubahan Sifat Kimia dan Biologi Tanah Pasca Kegiatan Perambahan Di Areal Hutan Pinus Reboisasi Kabupaten Humbang Hasundutan Provinsi Sumatera Utara
Abstrak: Encroachment is one of the causes of forest destruction. Forest soil fertility can decline in post-encroachment activities area. The purpose of this study was to determine changes in chemical and biological properties of soil in the pine forest encroachment caused by activities in the area of pine forest reforestation Humbang Hasundutan District, North Sumatra. This study uses the results of laboratory data analysis of soil, obtained from the Ministry of Environment. The research method used in this study is a composite soil samples by the method of purposive sampling. Soil samples taken at two locations: the pine forest and open area post-encroachment. Each Location be repeated three times. Further results of soil laboratory data were analyzed using descriptive and statistics by the T test at 95% confidence interval. Based on the analysis found that the pine forest clearing activities cause changes in soil chemical properties in the form of reduction in the number of COrganic content, N total, P Bray, Calcium, Magnesiun, Cation Exchange Capacity, and pH levels, however have increased the amount of potassium content. Pine forest encroachment activities cause change in biological soil properties in the form reduction in the number of soil microorganisms, solvent P bacteria, soil fungi, and soil respiration. Statistical analysis using T test for the 95% confidence interval stated that the pine forest clearing activity had effect on pH soil level, Calcium, and soil fungi.
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Judul: Perubahan Sifat Fisik Dan Kimia Tanah Akibat Kegiatan Penebangan Hutan dengan Teknik Reduced Impact Logging dan Teknik Conventional Logging.
Abstrak: Forest is a natural environment that could not be evaded from continuous interactions with humans who lived around. The interactions is one way of human to use forest potention. Human activity to use forest is very often result in forest and enviromental degradation. One solution that could keep forest sustainability is a sustainable forestry management which put forward the conservation aspects. In this forest management, soil as a vital resources for plants growth needs to have sufficient attention because soil is one of the most important habitat besides climate and topography factors. A research to evaluate the soil physical and chemical changes due to deforestation activity with RIL and CNV technique was carried out on CIFOR research plots. Upon the research, soil samples were taken from RIL, CNV, and Control plot. The soil samples were analyzed in Soil Physical Laboratory and Soil Chemical Laboratory in Soil Science and Resources Department, IPB. The data which is examined from physical and chemical analysis then statistically analyzed with Test of Between Subjects Effects, and continued by Duncan Test with p < 0,05 to view the relationship between RIL, CNV, and Control plot conditions. Results from physical analysis showed that bulk density on CNV plot is higher than that on RIL and Control plot. Meanwhile, the values of porosity, available water, and permeability on CNV are less than those on RIL and Control plot. Results from chemical analysis showed that C-Organic, Total-N, available P, K, and Cation Exchange Capacity (CEC) values on CNV plot are less than those on RIL and Control values. Statistics analysis showed that the values of bulk density, porosity, available water, C-Organic, Total-N, available P, K, and KTK on CNV, RIL, and Control plot are not significantly different. Meanwhile, the values of permeability on CNV plot is significantly different from RIL and Control plot. Examined soil physical changes are increasing of bulk density, decreasing of porosity, available water, and permeability. Examined soil chemical changes are decreasing of C-Organic content, decreasing of Total-N, decreasing of available P, decreasing of K, and decreasing of Cation Exchange Capacity (CEC). Physical and chemical changes on RIL plot are less than CNV plot, which means that RIL technique is better than CNV technique.
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Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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