Judul: Analisis Volatilitas Bahan Pangan Utama di Indonesia
Abstrak: Produk pertanian Indonesia memiliki fluktuasi harga (volatile food). Isu volatile food, isu Agreement of Agriculture (AOA), dan isu ketahanan pangan menjadi dasar dalam menganalisis volatilitas harga bahan pangan utama. Variabel bahan pangan utama yang digunakan pada penelitian ini, yaitu beras, gula pasir, dan minyak goreng menggunakan data time series. Analisis volatilitas harga dengan melihat harga daerah-daerah pada wilayah Indonesia bagian barat (Medan, Palembang, Jakarta, Semarang), tengah (Denpasar, Samarinda), dan timur (Makassar, Jayapura). Metode analisis yang digunakan dalam penelitian ini adalah analisis ekonometrika model peramalan Autoregressive Intergrated Moving Average (ARIMA) dan Autoregressive Conditional Heteroscedasticity (ARCH) / Generelized Autoregressive Conditional Heteroscedasticity (GARCH). Hasil analisis ARCH-GARCH menunjukkan bahwa harga bahan pangan utama mengalami volatilitas harga. Volatilitas harga beras tertinggi terjadi pada Kota Semarang, volatilitas gula pasir tertinggi pada Kota Samarinda, sedangkan volatilitas harga minyak goreng yang tertinggi pada Kota Semarang.
Keyword: ARCH-GARCH, ARIMA, beras, gula pasir, minyak goreng, volatilitas

Judul: Analysis of National Strategic Food Price Volatility and Its Effect on Inflation
Abstrak: Pangan merupakan kebutuhan primer yang harus terjaga stabilitas harganya. Beberapa periode terakhir harga sejumlah komoditas pangan strategis mengalami peningkatan. Penelitian ini bertujuan untuk menganalisis tingkat volatilitas harga minyak goreng, beras, cabai merah, bawang merah dan bawang putih serta pengaruhnya terhadap inflasi. Data yang digunakan adalah data harga kelima komoditas yang diperoleh dari Pusat Informasi Harga Pangan Strategis dan data inflasi diperoleh dari Bank Indonesia. Analisis yang dilakukan yakni Coefficient of Variation untuk melihat disparitas harga di seluruh provinsi di Indonesia dan pemodelan ARCH-GARCH untuk menganalisis volatilitas. Error Correction Model digunakan untuk menganalisis pengaruh volatilitas harga pangan terhadap inflasi. Hasil penelitian menunjukkan terdapat disparitas harga pangan antar waktu dan antar wilayah di Indonesia. Volatilitas harga kelima komoditas terjadi pada data harga tingkat nasional dan pada sejumlah wilayah amatan. Volatilitas harga minyak goreng serta beras berpengaruh signifkan terhadap inflasi pada jangka panjang. Sementara pada jangka pendek, volatilitas harga cabai merah dan volatilitas bawang merah bulan sebelumnya signifikan mempengaruhi tingkat inflasi, Food is a primary necessity that requires accessibility and price stability. In recent periods, the prices of some strategic food commodities have increased. The aim of this research is to analyze the level of price volatility of cooking oil, rice, red chili, shallots, and garlic, as well as their effect on inflation. The data used include the prices of these five commodities obtained from the Strategic Food Price Information Center and the inflation rate data obtained from the Bank of Indonesia. The analysis conducted includes the Coefficient of Variation to observe price disparities across all provinces in Indonesia and the ARCH-GARCH modeling to analyze volatility. The Error Correction Model is used to analyze the effect of food price volatility on inflation. The results show that price disparities occurs over time and across regions in Indonesia. Volatility in the prices of these five commodities occurs both at the national price level and in some observed regions. The price volatility of cooking oil and rice has a significant long-term effect on inflation. Meanwhile, in the short term, price volatility of red chili and shallots from the previous month have a significant effect on the inflation rate.
Keyword: ARCH-GARH, ECM, inflasi, pangan, volatilitas

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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