Judul: Evaluation of Green Open Space Availability and  Green City Concept Implementation in DKI Jakarta Province
Abstrak: Provinsi DKI Jakarta dengan peningkatan kegiatan pembangunan yang tinggi, membawa implikasi pada alih fungsi Ruang Terbuka Hijau (RTH) perkotaan menjadi lahan terbangun. Pentingnya keberadaan RTH tidak dapat dilepaskan dalam mendukung pengembangan konsep kota hijau di DKI Jakarta. Tujuan penelitian ini adalah mengevaluasi ketersediaan RTH dan implementasi konsep kota hijau di Provinsi DKI Jakarta. Metode penelitian yang digunakan adalah analisis spasial berbasis Geographic Information System (GIS) dan remote sensing, analisis kualitatif dan analisis kuantitatif berbasis Asian Green City Index. Pengamatan dilakukan pada periode tahun 2000, 2010, dan 2020. Hasil penelitian menunjukkan terjadi penurunan ketersediaan RTH, dari 33,70% pada tahun 2000, 23,47% pada tahun 2010, dan 19,50% pada tahun 2020. Pada penerapan konsep kota hijau, terjadi peningkatan performa DKI Jakarta, tahun 2000 performa berada pada tingkat below average (34,58%), average (44,85%) pada tahun 2010, dan menjadi above average (62,76%) pada tahun 2020. Hasil penelitian dapat menjadi referensi dalam merencanakan pembangunan di Provinsi DKI Jakarta agar tetap mempertahankan ketersediaan RTH dan berorientasi pada daya dukung lanskap., DKI Jakarta Province with a high increase in development activities, has an implication in the conversion of urban Green Open Space (GOS) into built-up land. The importance of urban green open space cannot be separated from supporting the development of the green city concept in DKI Jakarta. The purpose of this study was to evaluate the availability of GOS and the implementation of the green city concept in DKI Jakarta Province. The research method used is spatial analysis based on Geographic Information System (GIS) and remote sensing, qualitative analysis and quantitative analysis based on the Asian Green City Index. Observations were made in the period 2000, 2010 and 2020. The results showed that there was a decrease in the availability of GOS in the year of observation from 33,70% in 2000, 23,47% in 2010, and 19,50% in 2020. In the implementation of the green city concept, there is an increase performance of DKI Jakarta, from (34,58%) in 2000, average (44,85%) in 2010, and above average (62,76%) in 2020. The research results of the study can be used as a reference in planning development DKI Jakarta Province so that it remains oriented to maintain the availability of GOS and carrying capacity of the landscape.
Keyword: asian green city index, evaluation, green city, green open space

Judul: Evaluasi Penerapan Konsep Kota Hijau di Kota Jakarta
Abstrak: Green city is one of the concept for urban development towards the sustainable city. There are eight ideal indicators into a green city concept in Indonesia; green planning and design, green open space, green building, green waste, green transportation, green water, green energy, and green community. Jakarta is one of the major cities in Indonesia who have some urban problems such as; urbanization, traffic problem, flood, and also waste problem. The purpose of this study is to identify the application of the green city concept using gap analysis and evaluate the application of the concept using scoring method. The results from the formulation showed that Jakarta have related problems to eight green city indicators. The analysis showed that there is a gap between the ideal with actual condition in the green city immpelementation. Gaps caused by the application of green city concept is still in the early stages. The evaluation phase resulted that green transportation has the highest value of 50%, followed by green open space (45.83%), green planning and design (43.75%) green community (25%), green building (25%), green waste (25%), green water (12.50%), and green energy (10%).
Keyword: Jakarta, green city, gap analysis, evaluation

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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