Judul: Economic valuation of urban forest based on health cost approach (case study at Ragunan Zoo, Jakarta)
Abstrak: Air pollution in Jakarta which come from motor vehicle can affect trouble of health for society. Developing urban forest is one way to reduce air pollution in Jakarta because urban forest could give benefit by absorption and adsorption pollutant gases and particles. In the other hand, the development of urban forest was often unable to ”compete” if been faced with the opposite situation in the frame of economic. It cause, some of the urban forest converted into residence area, industrial area and trade area. Based on that problem, economic valuation of urban forest was an effort and urgent step in order to save the remained urban forest in Jakarta. The objectives of this research are to gain the potency of urban forest at Ragunan Zoo in reducing air pollution; and its economic value based on health cost approach. This research was held at district of Ragunan Zoo and Pasar Minggu, exactly in district of Ragunan and Pasar Minggu. Ragunan Zoo was legally stain up in 1966 with 135 ha, has a 14.957 indvidual trees from various species. The enumeration of urban forest ability potency in reducing air pollution was conducted by measuring the ability of trees at Ragunan Zoo in absorb and adsorb the pollutant gases and particles. Based on the calculation, the trees at Ragunan Zoo can adsorb Pb was equal to 1.407.244,38 µg, absorbing Pb was equal to 29.359.647 µg, adsorbing dust was equal to 417.602.217 mg, absorbing NO2 was equal to 6.684.445.733 µg, absorbing CO (by tree leaves) was equal to 19.094.004,21 µg/hour, and SO2 (by tree leaves) was equal to 301.097.758,7 µg/hour.
Keyword: 

Judul: The Value of Green Open Space in the Forest Park of Penjaringan, North Jakarta
Abstrak: Kepadatan penduduk dan aktivitas ekonomi yang terus meningkat dapat menyebabkan perubahan penggunaan lahan yang dapat menurunkan kualitas lingkungan terutama di wilayah perkotaan. DKI Jakarta termasuk kota yang merasakan dampak dari penurunan kualitas lingkungan. Keberadaan Ruang Terbuka Hijau merupakan salah satu upaya untuk menyeimbangkan dan memperbaiki kualitas lingkungan. Pada saat ini RTH di DKI Jakarta baru berjumlah 9,8% dari 30% target minimal yang ditetapkan berdasarkan Undang-undang Nomor 26 Tahun 2007. Taman Hutan Kota Penjaringan (THKP) merupakan bentuk dari RTH yang berada di DKI Jakarta. Keberadaan THKP mempunyai fungsi ekologis seperti daerah resapan air, penyerap karbon,dan kesejukan. Penelitian ini bertujuan untuk (1) Menganalisis persepsi pengunjung terhadap keberadaan Taman Hutan Kota Penjaringan, (2) Mengestimasi nilai WTP pengunjung terhadap keberadaaan Taman Hutan Kota Penjaringan, (3) Mengestimasi nilai ekonomi guna tidak langsung Taman Hutan Kota Penjaringan.Metode yang digunakan dalam penelitian ini adalah skala likert, Contingent Valuation Method (CVM), Pendekatan harga pasar, benefit transfer dan replacement cost. Hasil pada penelitian ini menunjukkan bahwa persepsi pengunjung terhadap keberadaan Taman Hutan Kota Penjaringan adalah sangat baik. Estimasi nilai total WTP pengunjung sebesar Rp 28, Population density and economic activity that continues to increase can lead to changes in land use that can reduce environmental quality, especially in urban areas. DKI Jakarta is one of the cities that feel the impact of the decline in environmental quality. The existence of Green Open Space is one of the efforts to balance and improve the quality of the environment.. Currently, green open space in DKI Jakarta is only 9.8% of the 30% minimum target set based on Law No. 26 of 2007. Penjaringan City Forest Park (THKP) is a form of green open space located in DKI Jakarta. The existence of THKP has ecological functions such as water catchment areas, carbon sinks, and coolness. This study aims to (1) analyze visitors' perceptions of the existence of the Penjaringan City Forest Park, (2) estimate the WTP value of visitors to the existence of the Penjaringan City Forest Park, (3) estimate the economic value for the indirect use of the Penjaringan City Forest Park. The method used in this study These are Likert scale, Contingent Valuation Method (CVM), market price approach, benefit transfer and replacement cost. The results of this study indicate that the visitor's perception of the existence of the Penjaringan City Forest Park is very good. The estimated total WTP value for visitors is IDR 8,615,503,707 / year. The total economic value for indirect use is IDR 224.563.442,30/year.
Keyword: Contingent Valuation Method, Hutan Kota, Nilai guna tidak langsung, Valuasi ekonomi, Willingness to pay, Economic Value, Indirect use value

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.
Keyword: