Judul: Shallot Price Transmission in Indonesia during The Covid-19 Pandemic
Abstrak: Bawang merah merupakan salah satu komoditas sayuran yang penting bagi masyarakat Indonesia karena fungsinya sebagai bumbu masak yang utama sehingga permintaan bawang merah cenderung meningkat. Pada saat pandemi Covid-19 harga bawang merah mengalami kenaikan harga. Kenaikan harga bawang merah diduga disebabkan karena distribusi yang tidak normal (adanya Pembatasan Sosial Berskala Besar/PSBB) dan musim tanam yang mundur sejak 2019. Penelitian ini bertujuan untuk menganalisis transmisi harga bawang merah tingkat produsen dan konsumen pada saat pandemi Covid-19. Data yang digunakan merupakan data time series (runtun waktu) harian dari Maret 2020 hingga Maret 2021. Analisis menggunakan pendekatan Vector Error Correction Model (VECM). Hasil estimasi VECM menunjukkan bahwa harga bawang merah pada tingkat produsen dan konsumen dalam jangka panjang mengalami transmisi harga satu arah, dimana perubahan harga yang terjadi di konsumen memengaruhi harga pada produsen. Pada jangka pendek tidak terjadi transmisi harga. Adanya transmisi harga satu arah dalam jangka panjang dan tidak terjadinya transmisi harga dalam jangka pendek antara prosuden dan konsumen dapat mengindikasikan bahwa lembaga pemasaran bawang merah di Indonesia tidak efisien selama pandemi Covid-19., Shallots are one of the important vegetable commodities for the people of Indonesia because of their function as the main cooking spice so that the demand for shallots tends to increase. During the Covid-19 pandemic, the price of shallots increased. The increase in the price of shallots is thought to be due to an abnormal distribution (the existence of Large-Scale Social Restrictions/PSBB) and the delayed planting season since 2019. This study aims to analyze the transmission of shallot prices at the producer and consumer levels during the Covid-19 pandemic. The data used is daily time series data from March 2020 to March 2021. The analysis uses the Vector Error Correction Model (VECM) approach. The results of the VECM estimation show that the price of shallots at the producer and consumer levels in the long run experiences one-way price transmission, where price changes that occur in consumers affect prices to producers. In the short term there is no price transmission. The existence of one-way price transmission in the long term and the absence of short-term price transmission between producers and consumers may indicate that shallot marketing institutions in Indonesia are inefficient during the Covid-19 pandemic.
Keyword: Covid-19 Pandemic, Price Transmission, Shallots, VECM

Judul: Analysis of Horticultural Commodity Food Price Volatility Before and During the Covid-19 Pandemic
Abstrak: Komoditas hortikultura seperti bawang merah, cabai merah, dan cabai rawit mengalami fluktuasi harga yang sangat berfluktuasi selama tahun 2019–2021. Permintaan komoditas tersebut memiliki sifat tidak elastis sehingga harganya cenderung volatil. Penelitian ini ditujukan untuk menganalisis volatilitas harga bawang merah, cabai merah dan cabai rawit dan menganalisis faktor yang memengaruhi selama periode 2019-2020. Metode yang digunakan adalah analisis coefficient of variation (CV), ARCH-GARCH, dan VECM. Hasil penelitian dengan analisis CV menunjukkan bahwa fluktuasi ketiga komoditas masih berada pada batas wajar. Faktor yang memengaruhi perubahan harga bawang merah di Indonesia pada jangka pendek hanya harga bawang merah domestik, sedangkan pada jangka panjang faktor yang memengaruhi perubahan harga bawang merah Indonesia yaitu nilai tukar, suku bunga, dan inflasi. Untuk cabai merah, faktor yang memengaruhi pada jangka pendek hanya inflasi, sedangkan pada jangka panjang faktor yang memengaruhi perubahan harga cabai merah yaitu inflasi, suku bunga, dan nilai tukar. Hasil IRF menunjukkan bahwa guncangan variabel faktor terhadap perubahan harga bawang merah dan cabai merah Indonesia bervariasi antar periodenya. Hasil FEVD sampai periode lima tahun mendatang menunjukkan semua variabel memiliki persentase kontribusi dalam memengaruhi perubahan harga bawang merah dan cabai merah Indonesia., Horticultural commodities such as shallots, red chilies, and cayenne peppers experienced highly fluctuating prices during 2019 – 2021. Demand for these commodities has an inelastic nature so prices tend to be volatile. This study aims to analyze the price volatility of shallots, red chilies, and cayenne peppers and analyze the influencing factors during the 2019-2020 period. The method used is coefficient of variation (CV) analysis, ARCH-GARCH, and VECM. The results of the research using CV analysis showed that the fluctuations of the three commodities were still within reasonable limits. Factors that affect changes in Indonesian shallot prices in the short term are only domestic shallot prices, while in the long term the factors influencing changes in Indonesian shallot prices are exchange rates, interest rates, and inflation. For red chili, the only influencing factor in the short term is inflation, while in the long term the factors that influence changes in the price of red chili are inflation, interest rates, and exchange rates. The results of the IRF show that the shock of the factor variables to changes in the prices of Indonesian shallots and red chilies varies between periods. The results of the FEVD for the next five years show that all variables have a contribution percentage in influencing changes in the prices of Indonesian shallots and red chilies.
Keyword: ARCH-GARCH, Cayenne Pepper, Onion, Red Chili, Volatility

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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