Judul: Ekstraksi Fitur Venasi Daun Tumbuhan Obat Berbasis Geometri
Abstrak: Penelitian ini mengajukan metode untuk mengekstraksi venasi dengan pendekatan geometri. Metode geometri pada penelitian ini digunakan untuk mengekstraksi ciri dengan menghitung nilai straightness, different angle, length ratio, dan scale projection. Citra masukan merupakan citra biner yang telah tersegmentasi dengan baik. Data penelitian ini berupa citra daun tumbuhan obat yang dikelompokan berdasarkan empat tipe venasi, yaitu acrodromous, actinodromous, campylodromous, dan pinnate. Metode ini telah berhasil mengekstraksi empat ciri, yaitu straightness, different angle, length ratio, dan scale projection. Pengukuran kemiripan diterapkan untuk memprediksi tipe venasi daun. Hasil percobaan menunjukkan ciri different angle merupakan penciri terbaik. Nilai akurasi rata-rata cukup baik yaitu sebesar 80%. Hasil percobaan dengan penggabungan penciri menunjukkan nilai akurasi rata-rata sebesar 67.5%. Penelitian ini menunjukkan representasi geometri dengan nilai different angle dapat membedakan tipe venasi daun tumbuhan obat dengan baik.
Keyword: ekstraksi ciri, geometri, tumbuhan obat, venasi daun

Judul: . Segmentasi Venasi Citra Daun Tanaman Obat Menggunakan Matriks Hessian.
Abstrak: Penelitian ini mengajukan metode untuk mensegmentasi citra venasi daun tanaman obat menggunakan matriks Hessian. Venasi daun merupakan salah satu fitur biometrik yang dapat dijadikan penciri suatu tanaman. Fitur tersebut spesifik untuk setiap spesies sehingga dapat menjadi penciri suatu tanaman Matriks Hessian merupakan metode deteksi tepi dengan turunan kedua yang dapat mensegmentasi citra berdasarkan kelompok strukturnya melalui nilai eigen piksel citra tersebut. Proses thinning dilakukan untuk menghasilkan citra yang siap ekstraksi. Sebagai tambahan, operasi morfologi dilakukan untuk memperbaiki garis rusak atau venasi yang tidak terhubung. Metode diujikan pada empat tipe venasi daun dari 346 sampel digital. Evaluasi visual yang dilakukan menunjukkan bahwa metode yang diajukan dapat digunakan untuk mengekstrak venasi primer, sekunder, dan tersier. Metode ini menjanjikan untuk membantu botanis dan taksonomis untuk mengidentifikasi tanaman obat secara otomatis.
Keyword: deteksi tepi, matriks Hessian, segmentasi venasi daun

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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