Judul: Farmer Adaptive Capacity to Climate Change in Strengthening Rice Sufficiency in Sumedang Regency, West Java Province
Abstrak: Greenhouse gas emission leads to global warming, which is fundamental to the current food security problem. An increase in global temperature of ~4°C or more above late-20th-century level, combined with increasing food demand, would pose large risks to food security globally and regionally. There are growing evidences that even at just 1°C of warming there are negative impacts for major crops like rice and corn. It is also indicated that the rate of global warming in the next decades is projected to be substantially higher than that in the last decades. Smallholder farmers, whose livelihood relies to the greatest extent on agriculture, have been reported worldwide to be one of those most affected by the adverse implication of climate change. Previous studies indicated that smallholder farmers have assumed some adaptation measures in their existing farming practices, which range from adjustment on planting calendar to investment on input and infrastructure. Their existing adaptations, however, have been reported to be inadequate and still leave substantial residual impacts untapped. The study aimed to examine existing farmer adaptive capacity to climate change and explore its future strengthening alternatives to improve the rice sufficiency at household level. Specifically, the objectives of the research were:(1) To verify the change of climatic condition in the study area and estimate its impact on rice yield under various types of existing farming practices, (2) To assess the effect of current and future climatic condition on farmers’ household rice sufficiency under the existing adaptation practices, (3) To assess farmers’ household vulnerability to the impact of current and future climatic condition on their household rice sufficiency, and (4) To identify the factors determining farmers’ existing adaptation practices. The assessment of current climate indicated an increasing trend in the annual average of minimum and maximum temperature (TMin and TMax) during 1981 – 2010, while the annual rainfall showed a decreasing trend during the same period. Furthermore, climate projection for near (2011 – 2040) and far-future (2041 – 2070) period generated by the 17 General Circulation Models (GCMs) under climate change scenario of Representative Concentration Pathways (RCP)4.5 also indicated that average annual rainfall has been projected to decrease by 6.81% and 7.34%, respectively. Meanwhile, the TMin and TMax were projected to increase by 0.65oC and 0.69oC for near-future, and then further increased by 1.23oC and 1.28oC for far-future, respectively. Similar changes in climatic condition were indicated to slightly higher extent under RCP8.5 for near- and far-future periods. The assessment of rice yield under current climate suggested that during 1990 – 2010, rice yield in the study area has been fluctuating. Furthermore, the simulated rice yield generated by CROPWAT indicated that a reduction in rice yield was projected to occur in the near- and far-future. Rice yield has been projected to decrease by 32.00% and 31.81%, in comparison to baseline, for nearfuture under RCP8.5 and RCP4.5, respectively. The reduction extended, with a slightly higher degree, to the far-future. The reduction was sensitive to variation in vii the existing farming practices. The shifting of planting time to better match rainfall pattern reduced the rice yield reduction by
Keyword: Climate change, Impact, Vulnerability, Adaptation

Judul: Assessment of Climate Change Mitigation and Adaptation among Smallholder Farmers in Dramaga Sub-district, Bogor, Indonesia
Abstrak: Human-induced climate change is considered a threat to communities and the natural system, in particular, agriculture, forestry, economy, health, and well-being. Climate change poses a 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 a rain-fed agriculture system. Meanwhile, Farmer’s responses could play a 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 the world’s many regions is 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, 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 Landcover map for 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 the 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, the majority of farmers are aware of climate change, where they felt that climate is changing. Most farmers are practicing some common adaptation measure based on their experiences. Further, they have been practicing few mitigation measures as well. Climate events owing to the rainfall variation, Temperature rise, and land-use change threat smallholder farmers. Results of the
Keyword: Land-use changes, Climate Change, Climate Variability

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