Judul: Analysis of Potential Non-Timber Forest Products in North Sumatra
Abstrak: Sumatera Utara memiliki potensi Hasil Hutan Bukan Kayu yang besar karena memiliki kawasan hutan yang luas. Komoditas HHBK di Sumatera Utara masih belum dimanfaatkan secara optimal. Tujuan penelitian ini mengetahui jenis HHBK yang berpotensi di Sumatera Utara. Jenis-jenis HHBK yang tercatat di Dinas Kehutanan Provinsi Sumatera Utara yaitu getah pinus, rotan manau, daun nilam, biji rotan, cengkeh, daun cengkeh, rotan sega (taman), rotan semambu, madu, dan nira. Data dan informasi diperoleh melalui hasil data sekunder yang berasal dari Dinas Kehutanan Sumatera Utara, situs internet resmi Badan Pusat Statistik Sumatera Utara, jurnal serta buku pustaka yang mendukung. Hasil penelitian menunjukkan jenis HHBK yang paling berpotensi pada saat ini di Sumatera Utara adalah getah pinus karena getah pinus memiliki Provisi Sumber Daya Hutan (PSDH) yang meningkat setiap tahunnya. PSDH yang dihasilkan getah pinus di Sumatera Utara dapat menambah pemasukan pendapatan Provinsi Sumatera Utara dan didukung oleh tempat tumbuh yang sesuai untuk pertumbuhan pinus berdasarkan kondisi iklim dan edafis., North Sumatra has great potential for non-timber forest products (NTFP) because it has a large forest area. NTFP commodities in North Sumatra are still not used optimally. The purpose of this study was to determine the types of NTFPs that have the potential in North Sumatra. The types of NTFPs recorded at the North Sumatra Provincial Forestry Service are pine resin, manau rattan, patchouli leaves, rattan seeds, cloves, clove leaves, sega (taman) rattan, semambu rattan, honey, and nira. Data and information were obtained through secondary data from the North Sumatra Forestry Service, the official website of the Central Statistics Agency of North Sumatra, journals and books that support. The results showed that currently the most potential NTFP species in North Sumatra is pine resin because pine resin has a Forest Resource Provision (FRP) which increases every year. FRP produced by pine resin in North Sumatra can increase the income of the Province of North Sumatra and is supported by suitable growing places for pine growth based on climatic and edaphic conditions.
Keyword: NTFPs, pine resin, FRP, potential

Judul: Studi Literatur Aneka Macam Hasil Hutan Bukan Kayu di Indonesia dan Manfaatnya
Abstrak: Paradigma lama dalam mengelola hutan hanya menekankan mengambil kayu namun mengabaikan hasil hutan bukan kayu (HHBK). Paradigma baru mengalihkan sudut pandang dari hutan sebagai sumber penghasil kayu, kepada hutan sebagai sumber daya alam yang bersifat multi fungsi dan multi guna. Paradigma ini memberi tahu bahwa potensi dan produk HHBK merupakan salah satu sumber daya hutan yang memiliki keunggulan komparatif. Tujuan penelitian ini adalah untuk mengetahui pengertian dan klasifikasi HHBK yang digunakan dan jenis-jenis HHBK yang terdapat di Indonesia serta pemanfaatannya. Data yang dikumpulkan dalam studi literatur ini adalah data sekunder yang diperoleh dari buku, jurnal, dan dokumen lain yang terkait dengan HHBK dan manfaatnya. Pengertian dan klasifikasi HHBK yang digunakan dalam literatur sebagian besar bersumber dari Peraturan Menteri Kehutanan Nomor P.35/Menhut-II/2007. HHBK yang terdapat di Indonesia sangat beragam demikian juga dengan pemanfaatannya. Beberapa diantaranya yaitu damar, rotan, bambu, madu, kayu putih, gaharu, dan kayu manis. Pemanfaatan HHBK di Indonesia masih tergolong sederhana karena masih digunakan secara sederhana untuk kebutuhan masyarakat, walaupun di beberapa lokasi sudah ada pengolahan lebih lanjut terhadap beberapa jenis HHBK yang meningkatkan nilai HHBK tersebut., The old paradigm in managing forests only emphasizes taking wood but ignores non-timber forest products (NTFPs). The new paradigm shifts the point of view from forests as a source of wood production, to forests as natural resources that are multi-functional and multi-purpose. This paradigm tells us that the potential and products of NTFPs are one of the forest resources that have a comparative advantage. The purpose of this study was to determine the definition and classification of NTFPs used and the types of NTFPs found in Indonesia and their uses. The data collected in this literature study is secondary data obtained from books, journals, and other documents related to NTFPs and their benefits. The definition and classification of NTFPs used in the Indonesian literature mostly comes from the Minister of Forestry Regulation Number P.35/Menhut-II/2007. NTFPs found in Indonesia are very diverse as are their uses. Some of them are resin, rattan, bamboo, honey, eucalyptus, agarwood, and cinnamon. Utilization of NTFPs in Indonesia is still relatively simple because they are still used simply for the needs of the community, although in some locations there has been further processing of several types of NTFPs that increase the value of these NTFPs.
Keyword: NTFPs, classification, definition, utilization

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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