Judul: The Role of Tengger Tribe Customary Law in the  Conservation of Natural Resources in the Bromo Tengger Semeru National Park
Abstrak: Kelestarian hutan salah satunya dipengaruhi oleh partisipasi masyarakat lokal. Kearifan lokal berupa hukum adat merupakan aturan hidup bagi masyarakat lokal yang bersangkutan sehingga harus menjadi pertimbangan dalam pengelolaan hutan, terutama dalam pengelolaan kawasan hutan konservasi di Indonesia. Penelitian ini bertujuan menilai hukum adat Suku Tengger di Desa Ngadas terkait pelestarian sumber daya alam kawasan Taman Nasional Bromo Tengger Semeru. Metode pengumpulan data yang digunakan yaitu observasi lapang, wawancara, dan pengisian kuesioner lalu dianalisis menggunakan deskriptif kualitatif. Hasil penelitian menunjukkan bahwa Suku Tengger memiliki hukum adat yang selaras dengan kebijakan nasional. Kepatuhan masyarakat terhadap hukum adat termasuk pada kategori patuh sehingga hukum adat masih terus berkelanjutan terutama terkait pelestarian sumber daya alam. Hukum adat juga memiliki kontribusi dalam hal konservasi tanah, air, tumbuhan, dan ekosistem hutan karena masyarakat masih mengimplementasikan hukum adat dengan baik dalam pemanfaatan sumber daya alam., Forest sustainability is influenced by the participation of local communities. Local wisdom in the form of customary law is a rule of life for the local community. It must be taken into consideration in forest management, especially in the management of conservation forest areas in Indonesia. This study aims to assess the customary law of the Tengger Tribe in Ngadas Village related to the preservation of natural resources in the Bromo Tengger Semeru National Park. Data collection methods used are field observations, interviews, also questionnaires and then analyzed with using descriptive qualitative. The results shows that the Tengger Tribe has customary laws that are in line with national policies. Community compliances with customary law is in the obedient category so that customary law is still sustainable, especially to the related preservation in natural resources. Customary law also has a great contribution in terms of conservation of soil, water, and forest ecosystem. The community still implements customary law well in the utilization of natural resources.
Keyword: Hukum adat, pelestarian, sumber daya alam, Suku Tengger, Taman Nasional Bromo Tengger Semeru

Judul: Studi Konservasi Sumberdaya Alam Hayati pada Masyarakat Tengger di Resort Ranu Pani, Taman Nasional Bromo Tengger Semeru
Abstrak: Ranu Pani village is an enclave village located in a area Ranu Pani Resort, Bromo Tengger Semeru National Park. Purpose of this study was to access the understanding and motivation of Tengger society, the level of economic dependency, and examines the real action of conservation. Methods in use begins with a literature study, field observation, and questionnaires. The trust believed that the forest is the system of life that must be preserved for the sake of happiness the offspring, forming positiveness on Tengger society to maintain the forest in order to preservein an hereditary manner, utilization done very limited only adoption of kindling the trees that is dead and retrieval grass for cattle course. The economic society derived from the results of the field so as not to be depended from biological resources in the forest. Ranu Pani village society sometimes actively in conservation activities through planting, forest ares extinguish the blaze, and joined in the conservation cadre society ang public patner of rangers. Various counseling who regularly performed by the management of Ranu Pani Resort, capable of being creates understanding conservation for Ranu Pani society so take care of security of the area an understand the established rules.
Keyword: Ranu Pani Resort, Tengger society, conservation

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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