Judul: The Role of Riparian Vegetation on the Water Quality of the Cigadog River, Ciwidey District, Bandung Regency
Abstrak: Vegetasi pada sempadan sungai berperan dalam menjaga kualitas air sungai. Aliran Sungai Cigadog pada Kecamatan Ciwidey, Kabupaten Bandung merupakan salah satu sungai yang berada dalam kawasan sub-DAS Ciwidey dengan aktivitas manusia yang padat di sekitarnya. Penelitian ini bertujuan untuk menganalisis status kualitas air aliran Sungai Cigadog pada segmen vegetasi sempadan sungai di Kecamatan Ciwidey, Kabupaten Bandung. Tahapan yang dilakukan dalam penelitian ini terdiri penentuan kondisi fisik sungai, penentuan kualitas air sungai, penentuan kondisi vegetasi ruang terbuka hijau sempadan sungai, studi pustaka, dan analisis data. Penentuan status kualitas air sungai dilakukan melalui analisis debit air sungai, penentuan kualitas air berdasarkan parameter fisik-kimia dan parameter biologi, serta perhitungan leaf area index (LAI) dan analisis vegetasi. Hasil analisis data menunjukkan status kualitas air Sungai Cigadog masuk ke dalam kategori ‘sedang’ karena pengaruh vegetasi di sepanjang sempadan sungai, ditunjukkan dengan perbedaan kualitas air pada titik inlet dan outlet sungai pada kawasan vegetasi sempadan sungai., Riparian vegetation plays a role in maintaining river water quality. The flow of the Cigadog River in Ciwidey District, Bandung Regency is one of the rivers in the Ciwidey sub-watershed area with dense human activity around it. This research aims to analyze the water quality status of the Cigadog River flowing in the river border vegetation segment in Ciwidey District, Bandung Regency. The stages carried out in this research consisted of determining the physical condition of the river, determining the quality of river water, determining the condition of green open space vegetation along the river border, literature study, and data analysis. The status of river water quality was determined through analysis of river water discharge, determining water quality based on physical-chemical parameters and biological parameters, as well as calculating the leaf area index (LAI) and vegetation analysis. The results of data analysis show that the water quality status of the Cigadog River is in the 'medium' category due to the influence of vegetation along the riparian, indicated by the difference in water quality at the river inlet and outlet points in the riparian vegetation area.
Keyword: vegetasi, Kualitas air sungai, sempadan sungai

Judul: Water Quality and Pollution Load in Ciwidey Sub-Watershed
Abstrak: Sungai Ciwidey merupakan salah satu hulu Sungai Citarum yang berada di wilayah Kabupaten Bandung. Pertumbuhan penduduk dan penggunaan lahan di Sub-DAS Ciwidey menyebabkan perubahan pada parameter kualitas air Sungai Ciwidey, terutama di bagian hilirnya. Penelitian ini bertujuan menganalisis kualitas air, besarnya beban pencemaran, total beban pencemaran dan pengaruhnya terhadap kualitas air di Sub-DAS Ciwidey. Analisis hasil pemantauan kualitas air Sungai Ciwidey dibandingkan dengan baku mutu kelas I. Besarnya beban pencemaran dihitung menggunakan metode rapid assessment. Analisis kualitas air menunjukkan pencemaran bahan organik dengan indikasi tingginya nilai biological oxygen demand (BOD), chemical oxygen demand (COD), dan fecal coliform. Parameter lain yang melebihi baku mutu adalah total suspended solid (TSS), total fosfat, besi (Fe), mangan (Mn), seng (Zn), dan detergen total. Beban pencemaran terbesar berasal dari kegiatan industri. Total beban pencemaran sebesar BOD 70,9672 ton/bulan; COD 116,6503 ton/bulan; TSS 45,3445 ton/bulan; total nitrate (TN) 0,0387 ton/bulan; dan total phosphate (TP) 0,0172 ton/bulan. Konsentrasi beban pencemar terbesar terhadap debit air terjadi pada bulan Agustus dan terkecil pada bulan Januari., Ciwidey River is one of the headwaters of the Citarum River in Bandung Regency area. Population growth and land use in Ciwidey Sub-watershed have caused changes in the water quality parameters of the Ciwidey River, especially in the downstream part. This research aims to analyze water quality, the magnitude of the pollution load, total pollution load and its effect on water quality in the Ciwidey Sub-watershed. Analysis of the results of monitoring water quality of Ciwidey River compared to class I quality standards. Meanwhile, pollution load was calculated using rapid assessment method. Water quality analysis shows organic material pollution with indicate by high biological oxygen demand (BOD), chemical oxygen demand COD and fecal coliform values. Other parameters that exceed quality standards are total suspended solid (TSS), total phosphate, iron (Fe), manganese (Mn), zinc (Zn), and total detergent. The largest pollution load comes from industrial factories with BOD 70,9672 tons/month; COD 116,6503 tons/month; TSS 45,3445 tons/month; total nitrate (TN) 0,0387 tons/month; and total phosphate (TP) 0,0172 tons/month. The largest concentration of pollutant loads to water discharge occurs in August and the smallest in January.
Keyword: baku mutu, limbah, pencemaran air

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
Keyword: