Judul: Kajian Pengambilan Keputusan Pemilihan Jenis Pohon dalam Pengelolaan Hutan Rakyat (Kasus di Desa Bojonggedang, Kecamatan Rancah, Kabupaten Ciamis)
Abstrak: The development and management of community forests in fact now is facing some problems. One of them is related to the selection of seed. The seeds that farmers can get, have modest quality. On the other hand, the choice of good quality tree is determined by the quality of the good seed. In addition to seed selection in community forest management, we should also consider how the farmers run their community forests, therefore this study aims are: 1) to explain the conditions of community forest management at the study site, and 2) to describe the considerations of the tree species which planted by farmers. This study takes place at Bojonggedang Village, Rancah Sub District, Ciamis Regency. The method for selecting respondents is purposive sampling method, with total respondents are 30 peoples. The results of this study indicate that the process of forest management by farmers are: 1) preparation of land, 2) planting, and 3) maintenance with undetermined frequency. Farmers are not doing harvesting activities by themself, they submitted on middlemen for both logging and timber transportation. Processing of forest products by farmers only for personal consumption, not for sale. Economic consideration is a primary consideration in determining the type of tree seed that will be planted. It can be seen from the factor type of seed that produce faster; easier access to markets; and the stability of the selling price of these types.
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Judul: Pengambilan Keputusan Pemilihan Jenis Tanaman dan Pola Tanam di Lahan Hutan Negara dan Lahan Milik (Studi Kasus di Desa Sungai Langka Kecamatan Gedong Tataan Kabupaten Pesawaran Propinsi Lampung)
Abstrak: Agroferestry adoption studies about farmer’s decision making on tree planting have been conducted for many cases, but there was an important aspect that still had less concern about farmer views especially how they choose the plant species and planting pattern and why they do that. The aim of this study was to explain the farmer’s reasons when they choose a plant species and planting pattern with different land tenure systems, state forest and private land. Method used in this study was case study through analyzing plant species and planting pattern selection, financial flow, household revenue structure, and portfolio diversification. The results showed that: the farmer’s reasons were (1) cash income, (2) production continuity, (3) gestation period, (4) easy maintenance and harvest, (5) easy post harvest process, (6) tolerance to be planted with other plants, and (7) land tenure security (especially in state forest land); most farmers chose cacao species, with the main combination of planting pattern that consist of cacao and banana in state forest land, cacao and petai, cacao and durian in private land; all the planting pattern were financially feasible; the largest contribution was given by cacao at all planting patterns based on farmer household revenue structure, and portfolio diversification was not conducted by the farmers.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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