Judul: Oil price and macroeconomics variables effects on stock price index (comparative study: South East Asia, East Asia, Europe, and America)
Abstrak: Crude oil is one factor that drive the world economy today. Its price performance is benchmark for the performance of the world economy because of its role is considered important in production process. Seven major stock indices in Asia has increased significantly as well as the increase in oil price since early 2002. Data shows since 2003 until 2008, Hang Seng rose 54,78 percent, BSE increased 71,22 percent, JKSE increased 74,80 percent, KLSE rose 45,06 percent, Nikkei rose 30,25 percent, Strait Times rose 49,33 percent, and KOSPI rose 57,27 percent. The improvement of global oil price followed by rising indices in Asia is not in accordance with the transmission mechanism and raises the question whether there is positive movement towards the oil price movement of stock price indices in Asia, whereas some countries in Asia are oil importers, particularly East Asia and India. Influence oil price on the economy may be different. Oil exporting countries got advantange from positive trends in oil price because of their income increases with rising oil price, while higher oil price would make oil importing countries have to pay more for their oil needs. The purpose of this study was to analyze how oil price and macroeconomic variables affect on stock price index in South East Asia, East Asia, Europe, and America countries. The data is monthly time series data from January 2000 until December 2009. Then, it analyzed using VAR/VECM with analysis tools IRF, and FEVD. The result showed that generally in Asia, stock price index in all Southeast Asia as well as India and South Korea would respond negatively to the oil price. If there were an increase in world oil price, it would lower the stock price index in each of these Asian countries. Stock price indices in European countries, namely FTSE, DAX, CAC, and SMI indicate different results. In general, FTSE, DAX, and SMI would positively respond to oil price movements, different from others, CAC would respond negatively. As in Europe, mostly stock price indices in America has also responded positively in oil price, except in Brazil which responded negatively.
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Judul: Analysis of Stock Exchange, Mining Commodity, Exchange Rates, and Energy Sector Stock Index using Vector Error Correction Model
Abstrak: Sektor Energi merupakan salah satu sektor yang memiliki pengaruh signifikan terhadap pertumbuhan ekonomi suatu negara secara umum. Kenaikan pertumbuhan ekonomi selalu berkaitan dengan penggunaan energi, di mana perkembangan ekonomi yang terus meningkat akan mengakibatkan peningkatan permintaan akan energi. Oleh karena itu, penelitian ini bertujuan untuk menganalisis faktor yang berpengaruh terhadap indeks saham sektor energi di Indonesia menggunakan Vector Error Correction Model (VECM). Data yang digunakan adalah indeks saham sektor energi, harga minyak bumi, harga batu bara, harga gas, indeks Nikkei, indeks Shanghai, indeks Dow Jones, dan kurs periode Januari 2021 hingga Maret 2023. Hasil analisis VECM menunjukkan bahwa pada jangka pendek harga minyak bumi dan harga batu bara berpengaruh nyata terhadap indeks saham sektor energi. Pada jangka panjang peubah yang berpengaruh nyata adalah harga batu bara, harga gas, indeks Nikkei, dan kurs. Hasil analisis Impulse Response Function (IRF) menunjukkan adanya shock pada indeks saham sektor energi, harga minyak bumi, dan harga batu bara dapat meningkatkan indeks saham sektor energi. Sebaliknya, adanya shock indeks Nikkei dapat menurunkan indeks saham sektor energi. Hasil Forecast Error Variance Decomposition (FEVD) menunjukkan bahwa kontribusi peubah indeks saham sektor energi, harga minyak bumi, harga batu bara, dan harga gas sudah nyata dalam menjelaskan perilaku perubahan indeks saham sektor energi., Energy Sector is one of the sectors that has a significant impact on the overall economic growth of a country. Economic growth is always linked to energy consumption, as increasing economic development leads to higher energy demand. Therefore, this study aims to analyze the factors influencing the energy sector stock index in Indonesia using Vector Error Correction Model (VECM). The data used include the energy sector stock index, crude oil prices, coal prices, gas prices, Nikkei Index, Shanghai Index, Dow Jones Index, and exchange rates from January 2021 to March 2023. VECM analysis results indicate that in the short term, crude oil prices and coal prices have a significant impact on the energy sector stock index. In the long term, significant factors are coal prices, gas prices, Nikkei Index, and exchange rates. The Impulse Response Function (IRF) analysis reveals that shocks to the energy sector stock index, crude oil prices, and coal prices can increase the energy sector stock index. Conversely, shocks to the Nikkei Index can decrease the energy sector stock index. The Forecast Error Variance Decomposition (FEVD) results demonstrate that the contributions of the energy sector stock index, crude oil prices, coal prices, and gas prices are significant in explaining the behavior of changes in the energy sector stock index.
Keyword: FEVD, IDX Energy, IRF, VECM

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf