Judul: Key Influencing Factors and Spillover Effects of Unbalanced Development in Indonesia: A Spatial Approach
Abstrak: Ketimpangan ekonomi merupakan salah satu masalah utama pembangunan di Indonesia. Untuk mengatasi permasalahan tersebut, berbagai kebijakan telah ditempuh oleh pemerintah, terutama yang paling mencolok, yaitu ketimpangan antara kawasan barat dan kawasan timur Indonesia. Terlepas dari berbagai kebijakan yang telah diambil, gap pembangunan antara kawasan barat dan timur masih terus lebar. Hal ini disebabkan oleh tingginya ketergantungan terhadap permintaan domestik sehingga menyebabkan aktivitas ekonomi cenderung mengikuti daerah dengan ukuran pasar yang lebih besar (Firdaus, 2013). Penelitian terkait ketimpangan pembangunan di Indonesia telah menjadi fokus utama banyak penelitian. Namun, berbeda dengan penelitian – penelitian terdahulu, penelitian ini menggunakan pendekatan spasial yang belum pernah dilakukan oleh penelitian – penelitian sebelumnya dengan topik serupa. Hal ini didasari oleh pemikiran bahwa pembangunan ekonomi melibatkan interaksi antarwilayah, khususnya melalui migrasi tenaga kerja. Pemikiran tersebut sejalan dengan teori – teori dalam ketimpangan pembangunan seperti growth pole spillover (Richardson, 1976) dan tahapan pembangunan Williamson (1965). Penelitian ini memiliki dua tujuan, yaitu untuk menggambarkan tren ketimpangan pembangunan dan mengidentifikasi factor-faktor penentu ketimpangan pembangunan di Indonesia. Untuk menjawab tujuan tersebut, peneliti menggunakan Theil’s entropy index dan regresi data panel spasial. Theil index menunjukan bahwa meskipun ketimpangan antar provinsi di Indonesia masih cukup tinggi, trennya menunjukkan pola menurun selama periode analisis. Selanjutnya, analisis menggunakan regresi data panel spasial menunjukkan bahwa pembangunan ekonomi regional di Indonesia dipengaruhi oleh penanaman modal asing, pembentukan modal tetap, pengeluaran pemerintah, fasilitas kesehatan, modal manusia, dan kepadatan penduduk. Hasil analisis spasial juga menunjukkan adanya dampak spillover terhadap pendapatan per kapita., Regional inequality has become one of the most important development issues in Indonesia. Many policies have been implemented by the government to handle the problem, especially to reduce the development gap between Western and Eastern Indonesia. Regardless the many efforts, the development gap between Western and Eastern areas remains wide. This is especially caused by the higher dependency on domestic demand which causes economic activities tend to follow along areas with bigger market sizes (Firdaus, 2013). Many studies related to regional inequality have been conducted in Indonesia. However, unlike previous studies, this study employed a spatial approach which has not been concerned by other studies with similar topic. This is motivated by the thought that regional development would involve interaction among regions, especially through workers’ movement. The hypothesis is in line with the major theories in economic development, such as the growth pole spillover (Richardson, 1976) and Williamson’s (1965) development stages. This study has two objectives, to delineate the trend of development inequality and to identify key determinants of regional inequality in Indonesia. To answer these objectives, Theil’s entropy index and spatial panel data regression model were employed. Theil’s entropy index shows that despite high regional inequality among provinces, it shows a downward trend over the year. Furthermore, spatial panel data regression model confirms that regional economic development is influenced by foreign direct investment, fixed capital formation, government expenditure, health facilities, human capital, and population density. Spatial analysis also shows a spillover effect on per capita income.
Keyword: panel data, regional, spatial, spillover

Judul: Impact of Investment on Economic Disparities between Regions in Indonesia
Abstrak: Perbedaan pendapatan perkapita antar wilayah provinsi semakin besar dalam kurun waktu 4 tahun terakhir, sementara dalam kurun waktu tersebut investasi cenderung meningkat. Dengan demikian tujuan utama penelitian ini adalah mengukur tingkat ketimpangan antar wilayah berdasarkan Indeks Williamson dan menganalisis dampak investasi terhadap ketimpangan tersebut. Metode yang digunakan pada penelitian ini adalah analisis regresi data panel dan perhitungan indeks Williamson. Data dalam penelitian ini diperoleh dari Badan Pusat Statistik, BKPM dan Open Data PUPR. Hasil analisis menunjukan bahwa tingkat ketimpangan wilayah cenderung tinggi atau mendekati angka 1 dalam kurun waktu 4 tahun yaitu dengan rata-rata nilai indeks Williamson sebesar 0,71. Berdasarkan analis data panel menunjukan bahwa investasi berpengaruh negatif dan signifikan terhadap ketimpangan ekonomi antar wilayah. Variabel infrastruktur dan tingkat pengangguran terbuka bersama-sama berpengaruh positif dan signifikan terhadap ketimpangan ekonomi antar wilayah. dan variabel tingkat pendidikan berpengaruh negatif dan tidak signifikan terhadap ketimpangan ekonomi antar wilayah di Indonesia., The difference in per capita income between provinces has been getting higher in the last 4 years, while during this period investment tends to increase. Thus, the main objective of this study is to measure the level of inequality between regions based on the Williamson Index and to analyze the impact of investment on this inequality. The method used in this study is panel data regression analysis and the calculation of the Williamson index. The data in this study were obtained from the Central Statistics Agency, BKPM and PUPR Open Data. The results of the analysis show that the level of regional inequality tends to be high or close to number 1 in a period of 4 years, with an average Williamson index value of 0.71. Based on panel data analysis, it shows that investment has a negative and significant effect on economic inequality between regions. The infrastructure variable and the open unemployment rate together have a positive and significant effect on economic inequality between regions. and the variable level of education has a negative and insignificant effect on economic inequality between regions in Indonesia.
Keyword: investment, regional inequality, williamson index

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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