Judul: Laju Infiltrasi pada Berbagai Jenis Penggunaan Lahan di DAS Ciambulawung, Kampung Lebakpicung, Lebak-Banten
Abstrak: Air merupakan sumberdaya yang begitu penting karena sangat dibutuhkan oleh makhluk hidup. Air dan tanah memiliki hubungan yang sangat erat satu sama lain. Salah satu bentuk hubungan tersebut ditunjukkan dengan proses penyediaan air dalam tanah yang dibutuhkan makhluk hidup. Hal ini tidak terlepas dari peran afiltrasi. Tujuan penelitian ini adalah untuk mengetahui laju infiltrasi tanah di DAS Ciambulawung, Kp. Lebakpicung, Banten. Selain itu, penelitian ini juga menelaah pengaruh faktor penggunaan lahan dan sifat-sifat tanah terhadap besar kecilnya laju infiltrasi di lokasi penelitian. Untuk mencapai tujuan tersebut dilakukan pengukuran infiltrasi secara in-situ menggunakan infiltrometer ring ganda. Penelitian ini dilakukan di kawasan TNGHS dan Lab. Fisika Tanah, Balittan, Bogor pada rentang waktu Februari-Juli 2011. Penentuan sampel titik pengamatan dilakukan dengan menggunakan metode stratified random sampling dengan memperhatikan faktor penggunaan lahan dan sifat fisik tanah, sedangkan analisis data dilakukan dengan menggunakan analisis korelasi, regresi, dan regresi Stepwise. Hasil penelitian menunjukkan bahwa laju infiltrasi tanah di daerah penelitian berkisar pada kelas sedang sampai cepat. Penggunaan lahan yang berbeda berimplikasi pada jenis vegetasi, sifat-sifat tanah dan tingkat pengolahan yang berbeda. Hal inilah yang menyebabkan terjadinya laju infiltrasi yang berbeda. Berdasarkan hasil pengukuran lapang, didapatkan laju infiltrasi rata-rata pada lahan hutan adalah 51,5 cm/jam (sangat cepat), pada lahan sengon sebesar 15 cm/jam (cepat), pada lahan kebun campuran yaitu 5 cm/jam (agak cepat), dan pada lahan sawah yaitu 2,75 cm/jam (sedang).
Keyword: In-situ infiltration, Infiltrometer, Stratified random sampling, Stepwise regression

Judul: Infiltration rate in various land use types in Ciambulawung watershed, Lebakpicung village, Lebak-Banten.
Abstrak: Water is one of important resources to all living entities. Nonetheless, available water decreases by time. Water has been known having a close relation to soil. One was important factor on water availability is the infiltration. In this study, the relationship of land use and soil physical properties to infiltration rate ware studied. To achive the goal, infiltration was measured using double ring infiltrometer. The research took place in TNGHS area and the soil physics laboratory, Balittan, Bogor from February until July 2011. Samples were determined using stratified radom sampling method, based on land use and soil physical properties. Meanwhile, statistical analysis involved correlation analysis, and regression, especially stepwise regression. The result showed that soil infiltration rate ranged from moderate up to rapid. It was found that land use types tend to have a relationship with infiltration rate, as well as soil physical properties. Based on field measurements, infiltration rate in the forest area was about 51,5 cm/hours (very rapid), while in sengon plantation was 15 cm/ hours (rapid). It appears that mixed garden achieved fairly rapid infiltration (5 cm/ hours), which was quite similar to agricultural fields (2,75 cm/ hours; middle). Statistical analysis showed that variables tend to have multicollinearity. Land use presented by NDVI, did not correlate to flow infiltration. This means that NDVI value was less robust to estimate land use parameters. Meanwhile, analyses of soil characteristics, indicated that only rapid pore drainage, bulk dencity, particle dencity, and pemeability statistically influenced infiltration rate.
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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