Judul: Penerapan Metodetwo Step Cluster Dalam  Analisis Gerombol  (Studi Kasus : Data Potensi Desa Sensus Ekonomi 2003 Wilayah Jawa Barat)
Abstrak: Clustering is a process of grouping objects based on similarities . Some problems in cluster analysis are the different scale of measurement, large data sets and unspecified number of cluster. One approach to handle this problems is by using Two Step cluster method. The purpose of this research is to applicate Two Step cluster method by clustering villages residing in West Java. The result of Two Step cluster method are pre-cluster which early yielded at first phase counted eight clusters and optimal cluster which yielded at second phase counted three clusters. Members in first cluster are objects which is extreme outliers and cannot be grouped into other clusters. Villages which include into second clusters have rural characteristic. The village has wide farm, many agriculture households, but also has underdeveloped field of industries and also information and communications. So that, to improve village potency for this cluster, the variables which still have low growth level has to be increased. The third cluster has the characteristic of urban status. Village in this cluster has the closest distance to downtown, developed enough in the field of industry, information and communications, but still have the highest number for unemployment citizens.
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Judul: Aplikasi Metode TwoStep Cluster pada Ukuran Data Berbeda, Studi Kasus: Data Potensi Desa 2006 untuk Wilayah Jawa Barat.
Abstrak: Analisis gerombol dilakukan untuk mengidentifikasi struktur kelompok data sebenarnya dimana masing-masing kelompok memiliki kemiripan tersendiri. Permasalahan yang biasa ditemukan pada analisis gerombol yaitu data yang ada umumnya tidak hanya bertipe kontinu namun juga bertipe kategorik, serta dalam menentukan jumlah gerombol akhir yang dilakukan secara subyektif oleh peneliti. Metode TwoStep Cluster mampu memberi solusi untuk peubah data yang bertipe campuran antara peubah kontinu dan kategorik serta secara otomatis membentuk gerombol yang optimal bagi kebutuhan data yang sangat besar. Penerapan metode TwoStep Cluster dilakukan pada data Podes SE2006 untuk wilayah Jawa Barat yang memiliki ukuran data besar, kemudian dilakukan kembali pada data Bandung yang memiliki ukuran data kecil. Penggerombolan pada data Jawa Barat menghasilkan tiga gerombol yaitu gerombol perkotaan, pedesaan, dan industri. Sedangkan penggerombolan pada data Bandung menghasilkan dua gerombol yaitu gerombol perkotaan dan pedesaan. Terbentuknya gerombol yang berbeda pada data besar dan data kecil disebabkan oleh jumlah data yang berbeda sehingga rataan centroid pada gerombol yang terbentuk saat proses algoritma TwoStep Cluster berbeda. Perbandingan penerapan metode TwoStep Cluster pada data berukuran besar dengan data berukuran kecil, menghasilkan persentase kesesuaian cukup baik yaitu sebesar 66,32%.
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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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