Judul: Vulnerability Assessment of Chilli Farmers with IPCC AR5 Approach (Case Study: Citapen Village, Ciawi District, Bogor Regency)
Abstrak: Pertanian hortikultura memegang peran penting dalam perekonomian Indonesia dengan kontribusinya terus meningkat terhadap PDB. Khususnya tanaman sayuran, berkontribusi terhadap ketahanan pangan dan gizi dimana permintaannya diproyeksikan akan terus meningkat. Namun, pengembangan pertanian hortikultura menghadapi berbagai tantangan, salah satunya adalah perubahan iklim yang dapat mengancam ketersediaan produk hortikultura. Oleh karena itu, diperlukan strategi adaptasi dan mitigasi perubahan iklim. Penelitian ini bertujuan untuk menilai kerentanan petani cabai di Desa Citapen menggunakan penilaian IPCC AR5. Hasil penelitian menunjukkan bahwa keempat metode pendekatan matematis yang digunakan ((S-AC), ((S+AC)/2), S/AC, Matrix) menghasilkan kesimpulan yang sama, yaitu sebagian besar petani cabai memiliki tingkat kerentanan dengan kategori agak rendah dengan metode terbaik adalah metode pembagian. Beberapa faktor pendorong kerentanan antara lain terkait dengan sistem pengelolaan lahan, penyuluhan pertanian dan kelembagaan kelompok tani yang belum optimal, keterbatasan akses terhadap informasi iklim, termasuk pasar dan modal. Rekomendasi strategi adaptasi yang dapat dilakukan diantaranya peningkatan manajemen lahan dengan jadwal yang lebih terencana, pengembangan sistem pertanian polikultur, pengembangan kapasitas kelompok tani, penerapan teknologi yang lebih optimal, serta perluasan program kampung hortikultura dan sekolah lapang iklim., Horticultural agriculture plays an important role in the Indonesian economy with its growing contribution to GDP. Vegetable crops, in particular, contributes to food security and nutrition where demand is projected to continue to increase. However, the development of horticultural agriculture faces various challenges, one of which is climate change that can threaten the availability of horticultural products. Therefore, climate change adaptation and mitigation strategies are needed. This study aims to assess the vulnerability of chilli farmers in Citapen Village using the IPCC AR5 assessment. The results showed that the four mathematical approach methods used ((S-AC), ((S+AC)/2), S/AC, Matrix) resulted in the same conclusion, namely most of the chilli farmers have a level of vulnerability with a rather low category with the best method is the division method. Some of the factors driving vulnerability are related to land management systems, agricultural extension and farmer group institutions that are not optimal, limited access to climate information, including markets and capital. Recommendations for adaptation strategies that can be carried out include improving land management with a more planned schedule, developing polyculture farming systems, developing the capacity of farmer groups, implementing more optimal technology, and expanding the horticultural village programme and climate field schools.
Keyword: chilli farmers, IPCC-AR5, vulnerability assessment

Judul: Assessment of Climate Change Mitigation and Adaptation among Smallholder Farmers
Abstrak: Human-induced climate change is considered a threat to communities and the natural system, in particular, agriculture, forestry, economy, health, and wellbeing. Climate change poses great influence on crop productivity, food supply and food security. Indonesian farmers are the most vulnerable group prone to climate change risks, where they rely on rain-fed agriculture system. Meanwhile, Farmer’s responses could play significant role in fighting with changing climate and rising agricultural production. Extreme weather events namely flood and long dry season, are great concerns for Indonesia and the region. Moreover, land cover around world’s many regions are being changed at a rapid pace. Particularly, deforestation is the main recognized type of land cover changes and the main contributor to climate change. Where, human activities particularly, agriculture expansion is the main driver of land transformation. The objectives of this study is to detect rainfall and temperature trends of the past thirty years, identify land cover changes and trends, and evaluate smallholder farmer’s perception and their responses against changing climate in Dramaga Sub-district. Where, the Dramaga has a huge number of populations relying on rain-fed agriculture, as to feed themselves and support food security. Three main sources for obtaining data have been used in this study: a): Monthly rainfall and temperature data were obtained from the Dramaga Climatology Station of Meteorology, Climatology, and Geophysics Agency from the period 1990-2019. b): Satellite imageries Landsat 7 and landsat 8 operation land manager (OLI) with the 30 m resolution have been obtained from USGS online system. c): field data have been obtained from smallholder farmers using structured questionnaire and interview. In order to analyze the data, A Mann- Kendall statistical test has been run to detect the statistical significance of time series monthly rainfall and temperature data in comparison with the linear model. Likewise, to detect the land cover changes from 2000 to 2020, supervised classification has been carried out, and Land cover map for the 2000 and 2020 along with the changes detection have been prepared through Arc GIS 10.2. To find out climate change perception among smallholder farmers, descriptive statistics such as mean and standards deviation for the Likert scale statements analysis and a Chi-square test have been run to determine association among variables. The findings indicated no significant trends in the seasonal and annual rainfall in the past thirty years, whereas, annual mean and maximum temperature are rising significantly. Further, the annual minimum temperature does not show a statistically significant increase. Study Findings showed that, great areas in Bogor converted from vegetation – Agriculture (+27.2%), Vegetation – Built up (+12.1%), Vegetation – Bare land (+9.6%), forest – agriculture (+9.7%), and Forest – built up (+4.8%). Moreover, Approximately, 688 Ha land cover has been changed in Dramaga Sub-district in the past 20 years. In addition, majority of farmers are aware of climate change, where they felt that climate is changing. Most of farmers are practicing some common adaptation measure based on their experiences. Further, they have been practicing few mitigation measure as well. Climate events owing to the rainfall variation, Temperature rise, and land use change threat smallholder
Keyword: Climate-smart agriculture, food security, land-use changes, rain-fed agriculture

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix